--- a/src/testdir/test_functions.vim
+++ b/src/testdir/test_functions.vim
@@ -1,3557 +1,3557 @@
-" Tests for various functions.
-
-source shared.vim
-source check.vim
-source term_util.vim
-source screendump.vim
-import './vim9.vim' as v9
-
-" Must be done first, since the alternate buffer must be unset.
-func Test_00_bufexists()
-  call assert_equal(0, bufexists('does_not_exist'))
-  call assert_equal(1, bufexists(bufnr('%')))
-  call assert_equal(0, bufexists(0))
-  new Xfoo
-  let bn = bufnr('%')
-  call assert_equal(1, bufexists(bn))
-  call assert_equal(1, bufexists('Xfoo'))
-  call assert_equal(1, bufexists(getcwd() . '/Xfoo'))
-  call assert_equal(1, bufexists(0))
-  bw
-  call assert_equal(0, bufexists(bn))
-  call assert_equal(0, bufexists('Xfoo'))
-endfunc
-
-func Test_has()
-  call assert_equal(1, has('eval'))
-  call assert_equal(1, has('eval', 1))
-
-  if has('unix')
-    call assert_equal(1, or(has('ttyin'), 1))
-    call assert_equal(0, and(has('ttyout'), 0))
-    call assert_equal(1, has('multi_byte_encoding'))
-  endif
-  call assert_equal(1, has('vcon', 1))
-  call assert_equal(1, has('mouse_gpm_enabled', 1))
-
-  call assert_equal(0, has('nonexistent'))
-  call assert_equal(0, has('nonexistent', 1))
-
-  " Will we ever have patch 9999?
-  let ver = 'patch-' .. v:version / 100 .. '.' .. v:version % 100 .. '.9999'
-  call assert_equal(0, has(ver))
-
-  " There actually isn't a patch 9.0.0, but this is more consistent.
-  call assert_equal(1, has('patch-9.0.0'))
-endfunc
-
-func Test_empty()
-  call assert_equal(1, empty(''))
-  call assert_equal(0, empty('a'))
-
-  call assert_equal(1, empty(0))
-  call assert_equal(1, empty(-0))
-  call assert_equal(0, empty(1))
-  call assert_equal(0, empty(-1))
-
-  call assert_equal(1, empty(0.0))
-  call assert_equal(1, empty(-0.0))
-  call assert_equal(0, empty(1.0))
-  call assert_equal(0, empty(-1.0))
-  call assert_equal(0, empty(1.0/0.0))
-  call assert_equal(0, empty(0.0/0.0))
-
-  call assert_equal(1, empty([]))
-  call assert_equal(0, empty(['a']))
-
-  call assert_equal(1, empty({}))
-  call assert_equal(0, empty({'a':1}))
-
-  call assert_equal(1, empty(v:null))
-  call assert_equal(1, empty(v:none))
-  call assert_equal(1, empty(v:false))
-  call assert_equal(0, empty(v:true))
-
-  if has('channel')
-    call assert_equal(1, empty(test_null_channel()))
-  endif
-  if has('job')
-    call assert_equal(1, empty(test_null_job()))
-  endif
-
-  call assert_equal(0, empty(function('Test_empty')))
-  call assert_equal(0, empty(function('Test_empty', [0])))
-
-  call assert_fails("call empty(test_void())", ['E340:', 'E685:'])
-  call assert_fails("call empty(test_unknown())", ['E340:', 'E685:'])
-endfunc
-
-func Test_test_void()
-  call assert_fails('echo 1 == test_void()', 'E1031:')
-  call assert_fails('echo 1.0 == test_void()', 'E1031:')
-  call assert_fails('let x = json_encode(test_void())', ['E340:', 'E685:'])
-  call assert_fails('let x = copy(test_void())', ['E340:', 'E685:'])
-  call assert_fails('let x = copy([test_void()])', 'E1031:')
-endfunc
-
-func Test_islocked()
-  call assert_fails('call islocked(99)', 'E475:')
-  call assert_fails('call islocked("s: x")', 'E488:')
-endfunc
-
-func Test_len()
-  call assert_equal(1, len(0))
-  call assert_equal(2, len(12))
-
-  call assert_equal(0, len(''))
-  call assert_equal(2, len('ab'))
-
-  call assert_equal(0, len([]))
-  call assert_equal(0, len(test_null_list()))
-  call assert_equal(2, len([2, 1]))
-
-  call assert_equal(0, len({}))
-  call assert_equal(0, len(test_null_dict()))
-  call assert_equal(2, len({'a': 1, 'b': 2}))
-
-  call assert_fails('call len(v:none)', 'E701:')
-  call assert_fails('call len({-> 0})', 'E701:')
-endfunc
-
-func Test_max()
-  call assert_equal(0, max([]))
-  call assert_equal(2, max([2]))
-  call assert_equal(2, max([1, 2]))
-  call assert_equal(2, max([1, 2, v:null]))
-
-  call assert_equal(0, max({}))
-  call assert_equal(2, max({'a':1, 'b':2}))
-
-  call assert_fails('call max(1)', 'E712:')
-  call assert_fails('call max(v:none)', 'E712:')
-
-  " check we only get one error
-  call assert_fails('call max([#{}, [1]])', ['E728:', 'E728:'])
-  call assert_fails('call max(#{a: {}, b: [1]})', ['E728:', 'E728:'])
-endfunc
-
-func Test_min()
-  call assert_equal(0, min([]))
-  call assert_equal(2, min([2]))
-  call assert_equal(1, min([1, 2]))
-  call assert_equal(0, min([1, 2, v:null]))
-
-  call assert_equal(0, min({}))
-  call assert_equal(1, min({'a':1, 'b':2}))
-
-  call assert_fails('call min(1)', 'E712:')
-  call assert_fails('call min(v:none)', 'E712:')
-  call assert_fails('call min([1, {}])', 'E728:')
-
-  " check we only get one error
-  call assert_fails('call min([[1], #{}])', ['E745:', 'E745:'])
-  call assert_fails('call min(#{a: [1], b: #{}})', ['E745:', 'E745:'])
-endfunc
-
-func Test_strwidth()
-  for aw in ['single', 'double']
-    exe 'set ambiwidth=' . aw
-    call assert_equal(0, strwidth(''))
-    call assert_equal(1, strwidth("\t"))
-    call assert_equal(3, strwidth('Vim'))
-    call assert_equal(4, strwidth(1234))
-    call assert_equal(5, strwidth(-1234))
-
-    call assert_equal(2, strwidth('😉'))
-    call assert_equal(17, strwidth('Eĥoŝanĝo ĉiuĵaŭde'))
-    call assert_equal((aw == 'single') ? 6 : 7, strwidth('Straße'))
-
-    call assert_fails('call strwidth({->0})', 'E729:')
-    call assert_fails('call strwidth([])', 'E730:')
-    call assert_fails('call strwidth({})', 'E731:')
-  endfor
-
-  call assert_equal(3, strwidth(1.2))
-  call v9.CheckDefAndScriptFailure(['echo strwidth(1.2)'], ['E1013: Argument 1: type mismatch, expected string but got float', 'E1174: String required for argument 1'])
-
-  set ambiwidth&
-endfunc
-
-func Test_str2nr()
-  call assert_equal(0, str2nr(''))
-  call assert_equal(1, str2nr('1'))
-  call assert_equal(1, str2nr(' 1 '))
-
-  call assert_equal(1, str2nr('+1'))
-  call assert_equal(1, str2nr('+ 1'))
-  call assert_equal(1, str2nr(' + 1 '))
-
-  call assert_equal(-1, str2nr('-1'))
-  call assert_equal(-1, str2nr('- 1'))
-  call assert_equal(-1, str2nr(' - 1 '))
-
-  call assert_equal(123456789, str2nr('123456789'))
-  call assert_equal(-123456789, str2nr('-123456789'))
-
-  call assert_equal(5, str2nr('101', 2))
-  call assert_equal(5, '0b101'->str2nr(2))
-  call assert_equal(5, str2nr('0B101', 2))
-  call assert_equal(-5, str2nr('-101', 2))
-  call assert_equal(-5, str2nr('-0b101', 2))
-  call assert_equal(-5, str2nr('-0B101', 2))
-
-  call assert_equal(65, str2nr('101', 8))
-  call assert_equal(65, str2nr('0101', 8))
-  call assert_equal(-65, str2nr('-101', 8))
-  call assert_equal(-65, str2nr('-0101', 8))
-  call assert_equal(65, str2nr('0o101', 8))
-  call assert_equal(65, str2nr('0O0101', 8))
-  call assert_equal(-65, str2nr('-0O101', 8))
-  call assert_equal(-65, str2nr('-0o0101', 8))
-
-  call assert_equal(11259375, str2nr('abcdef', 16))
-  call assert_equal(11259375, str2nr('ABCDEF', 16))
-  call assert_equal(-11259375, str2nr('-ABCDEF', 16))
-  call assert_equal(11259375, str2nr('0xabcdef', 16))
-  call assert_equal(11259375, str2nr('0Xabcdef', 16))
-  call assert_equal(11259375, str2nr('0XABCDEF', 16))
-  call assert_equal(-11259375, str2nr('-0xABCDEF', 16))
-
-  call assert_equal(1, str2nr("1'000'000", 10, 0))
-  call assert_equal(256, str2nr("1'0000'0000", 2, 1))
-  call assert_equal(262144, str2nr("1'000'000", 8, 1))
-  call assert_equal(1000000, str2nr("1'000'000", 10, 1))
-  call assert_equal(1000, str2nr("1'000''000", 10, 1))
-  call assert_equal(65536, str2nr("1'00'00", 16, 1))
-
-  call assert_equal(0, str2nr('0x10'))
-  call assert_equal(0, str2nr('0b10'))
-  call assert_equal(0, str2nr('0o10'))
-  call assert_equal(1, str2nr('12', 2))
-  call assert_equal(1, str2nr('18', 8))
-  call assert_equal(1, str2nr('1g', 16))
-
-  call assert_equal(0, str2nr(v:null))
-  call assert_equal(0, str2nr(v:none))
-
-  call assert_fails('call str2nr([])', 'E730:')
-  call assert_fails('call str2nr({->2})', 'E729:')
-  call assert_equal(1, str2nr(1.2))
-  call v9.CheckDefAndScriptFailure(['echo str2nr(1.2)'], ['E1013: Argument 1: type mismatch, expected string but got float', 'E1174: String required for argument 1'])
-  call assert_fails('call str2nr(10, [])', 'E745:')
-endfunc
-
-func Test_strftime()
-  CheckFunction strftime
-
-  " Format of strftime() depends on system. We assume
-  " that basic formats tested here are available and
-  " identical on all systems which support strftime().
-  "
-  " The 2nd parameter of strftime() is a local time, so the output day
-  " of strftime() can be 17 or 18, depending on timezone.
-  call assert_match('^2017-01-1[78]$', strftime('%Y-%m-%d', 1484695512))
-  "
-  call assert_match('^\d\d\d\d-\(0\d\|1[012]\)-\([012]\d\|3[01]\) \([01]\d\|2[0-3]\):[0-5]\d:\([0-5]\d\|60\)$', '%Y-%m-%d %H:%M:%S'->strftime())
-
-  call assert_fails('call strftime([])', 'E730:')
-  call assert_fails('call strftime("%Y", [])', 'E745:')
-
-  " Check that the time changes after we change the timezone
-  " Save previous timezone value, if any
-  if exists('$TZ')
-    let tz = $TZ
-  endif
-
-  " Force EST and then UTC, save the current hour (24-hour clock) for each
-  let $TZ = 'EST' | let est = strftime('%H')
-  let $TZ = 'UTC' | let utc = strftime('%H')
-
-  " Those hours should be two bytes long, and should not be the same; if they
-  " are, a tzset(3) call may have failed somewhere
-  call assert_equal(strlen(est), 2)
-  call assert_equal(strlen(utc), 2)
-  " TODO: this fails on MS-Windows
-  if has('unix')
-    call assert_notequal(est, utc)
-  endif
-
-  " If we cached a timezone value, put it back, otherwise clear it
-  if exists('tz')
-    let $TZ = tz
-  else
-    unlet $TZ
-  endif
-endfunc
-
-func Test_strptime()
-  CheckFunction strptime
-
-  if exists('$TZ')
-    let tz = $TZ
-  endif
-  let $TZ = 'UTC'
-
-  call assert_equal(1484653763, strptime('%Y-%m-%d %T', '2017-01-17 11:49:23'))
-
-  " Force DST and check that it's considered
-  let $TZ = 'WINTER0SUMMER,J1,J365'
-  call assert_equal(1484653763 - 3600, strptime('%Y-%m-%d %T', '2017-01-17 11:49:23'))
-
-  call assert_fails('call strptime()', 'E119:')
-  call assert_fails('call strptime("xxx")', 'E119:')
-  call assert_equal(0, strptime("%Y", ''))
-  call assert_equal(0, strptime("%Y", "xxx"))
-
-  if exists('tz')
-    let $TZ = tz
-  else
-    unlet $TZ
-  endif
-endfunc
-
-func Test_resolve_unix()
-  CheckUnix
-
-  " Xlink1 -> Xlink2
-  " Xlink2 -> Xlink3
-  silent !ln -s -f Xlink2 Xlink1
-  silent !ln -s -f Xlink3 Xlink2
-  call assert_equal('Xlink3', resolve('Xlink1'))
-  call assert_equal('./Xlink3', resolve('./Xlink1'))
-  call assert_equal('Xlink3/', resolve('Xlink2/'))
-  " FIXME: these tests result in things like "Xlink2/" instead of "Xlink3/"?!
-  "call assert_equal('Xlink3/', resolve('Xlink1/'))
-  "call assert_equal('./Xlink3/', resolve('./Xlink1/'))
-  "call assert_equal(getcwd() . '/Xlink3/', resolve(getcwd() . '/Xlink1/'))
-  call assert_equal(getcwd() . '/Xlink3', resolve(getcwd() . '/Xlink1'))
-
-  " Test resolve() with a symlink cycle.
-  " Xlink1 -> Xlink2
-  " Xlink2 -> Xlink3
-  " Xlink3 -> Xlink1
-  silent !ln -s -f Xlink1 Xlink3
-  call assert_fails('call resolve("Xlink1")',   'E655:')
-  call assert_fails('call resolve("./Xlink1")', 'E655:')
-  call assert_fails('call resolve("Xlink2")',   'E655:')
-  call assert_fails('call resolve("Xlink3")',   'E655:')
-  call delete('Xlink1')
-  call delete('Xlink2')
-  call delete('Xlink3')
-
-  silent !ln -s -f Xresolvedir//Xfile Xresolvelink
-  call assert_equal('Xresolvedir/Xfile', resolve('Xresolvelink'))
-  call delete('Xresolvelink')
-
-  silent !ln -s -f Xlink2/ Xlink1
-  call assert_equal('Xlink2', 'Xlink1'->resolve())
-  call assert_equal('Xlink2/', resolve('Xlink1/'))
-  call delete('Xlink1')
-
-  silent !ln -s -f ./Xlink2 Xlink1
-  call assert_equal('Xlink2', resolve('Xlink1'))
-  call assert_equal('./Xlink2', resolve('./Xlink1'))
-  call delete('Xlink1')
-
-  call assert_equal('/', resolve('/'))
-endfunc
-
-func s:normalize_fname(fname)
-  let ret = substitute(a:fname, '\', '/', 'g')
-  let ret = substitute(ret, '//', '/', 'g')
-  return ret->tolower()
-endfunc
-
-func Test_resolve_win32()
-  CheckMSWindows
-
-  " test for shortcut file
-  if executable('cscript')
-    new Xresfile
-    wq
-    let lines =<< trim END
-	Set fs = CreateObject("Scripting.FileSystemObject")
-	Set ws = WScript.CreateObject("WScript.Shell")
-	Set shortcut = ws.CreateShortcut("Xlink.lnk")
-	shortcut.TargetPath = fs.BuildPath(ws.CurrentDirectory, "Xresfile")
-	shortcut.Save
-    END
-    call writefile(lines, 'link.vbs')
-    silent !cscript link.vbs
-    call delete('link.vbs')
-    call assert_equal(s:normalize_fname(getcwd() . '\Xresfile'), s:normalize_fname(resolve('./Xlink.lnk')))
-    call delete('Xresfile')
-
-    call assert_equal(s:normalize_fname(getcwd() . '\Xresfile'), s:normalize_fname(resolve('./Xlink.lnk')))
-    call delete('Xlink.lnk')
-  else
-    echomsg 'skipped test for shortcut file'
-  endif
-
-  " remove files
-  call delete('Xlink')
-  call delete('Xdir', 'd')
-  call delete('Xresfile')
-
-  " test for symbolic link to a file
-  new Xresfile
-  wq
-  call assert_equal('Xresfile', resolve('Xresfile'))
-  silent !mklink Xlink Xresfile
-  if !v:shell_error
-    call assert_equal(s:normalize_fname(getcwd() . '\Xresfile'), s:normalize_fname(resolve('./Xlink')))
-    call delete('Xlink')
-  else
-    echomsg 'skipped test for symbolic link to a file'
-  endif
-  call delete('Xresfile')
-
-  " test for junction to a directory
-  call mkdir('Xdir')
-  silent !mklink /J Xlink Xdir
-  if !v:shell_error
-    call assert_equal(s:normalize_fname(getcwd() . '\Xdir'), s:normalize_fname(resolve(getcwd() . '/Xlink')))
-
-    call delete('Xdir', 'd')
-
-    " test for junction already removed
-    call assert_equal(s:normalize_fname(getcwd() . '\Xlink'), s:normalize_fname(resolve(getcwd() . '/Xlink')))
-    call delete('Xlink')
-  else
-    echomsg 'skipped test for junction to a directory'
-    call delete('Xdir', 'd')
-  endif
-
-  " test for symbolic link to a directory
-  call mkdir('Xdir')
-  silent !mklink /D Xlink Xdir
-  if !v:shell_error
-    call assert_equal(s:normalize_fname(getcwd() . '\Xdir'), s:normalize_fname(resolve(getcwd() . '/Xlink')))
-
-    call delete('Xdir', 'd')
-
-    " test for symbolic link already removed
-    call assert_equal(s:normalize_fname(getcwd() . '\Xlink'), s:normalize_fname(resolve(getcwd() . '/Xlink')))
-    call delete('Xlink')
-  else
-    echomsg 'skipped test for symbolic link to a directory'
-    call delete('Xdir', 'd')
-  endif
-
-  " test for buffer name
-  new Xbuffile
-  wq
-  silent !mklink Xlink Xbuffile
-  if !v:shell_error
-    edit Xlink
-    call assert_equal('Xlink', bufname('%'))
-    call delete('Xlink')
-    bw!
-  else
-    echomsg 'skipped test for buffer name'
-  endif
-  call delete('Xbuffile')
-
-  " test for reparse point
-  call mkdir('Xdir')
-  call assert_equal('Xdir', resolve('Xdir'))
-  silent !mklink /D Xdirlink Xdir
-  if !v:shell_error
-    w Xdir/text.txt
-    call assert_equal('Xdir/text.txt', resolve('Xdir/text.txt'))
-    call assert_equal(s:normalize_fname(getcwd() . '\Xdir\text.txt'), s:normalize_fname(resolve('Xdirlink\text.txt')))
-    call assert_equal(s:normalize_fname(getcwd() . '\Xdir'), s:normalize_fname(resolve('Xdirlink')))
-    call delete('Xdirlink')
-  else
-    echomsg 'skipped test for reparse point'
-  endif
-
-  call delete('Xdir', 'rf')
-endfunc
-
-func Test_simplify()
-  call assert_equal('',            simplify(''))
-  call assert_equal('/',           simplify('/'))
-  call assert_equal('/',           simplify('/.'))
-  call assert_equal('/',           simplify('/..'))
-  call assert_equal('/...',        simplify('/...'))
-  call assert_equal('//path',      simplify('//path'))
-  if has('unix')
-    call assert_equal('/path',       simplify('///path'))
-    call assert_equal('/path',       simplify('////path'))
-  endif
-
-  call assert_equal('./dir/file',  './dir/file'->simplify())
-  call assert_equal('./dir/file',  simplify('.///dir//file'))
-  call assert_equal('./dir/file',  simplify('./dir/./file'))
-  call assert_equal('./file',      simplify('./dir/../file'))
-  call assert_equal('../dir/file', simplify('dir/../../dir/file'))
-  call assert_equal('./file',      simplify('dir/.././file'))
-  call assert_equal('../dir',      simplify('./../dir'))
-  call assert_equal('..',          simplify('../testdir/..'))
-  call mkdir('Xsimpdir')
-  call assert_equal('.',           simplify('Xsimpdir/../.'))
-  call delete('Xsimpdir', 'd')
-
-  call assert_fails('call simplify({->0})', 'E729:')
-  call assert_fails('call simplify([])', 'E730:')
-  call assert_fails('call simplify({})', 'E731:')
-  call assert_equal('1.2', simplify(1.2))
-  call v9.CheckDefAndScriptFailure(['echo simplify(1.2)'], ['E1013: Argument 1: type mismatch, expected string but got float', 'E1174: String required for argument 1'])
-endfunc
-
-func Test_pathshorten()
-  call assert_equal('', pathshorten(''))
-  call assert_equal('foo', pathshorten('foo'))
-  call assert_equal('/foo', '/foo'->pathshorten())
-  call assert_equal('f/', pathshorten('foo/'))
-  call assert_equal('f/bar', pathshorten('foo/bar'))
-  call assert_equal('f/b/foobar', 'foo/bar/foobar'->pathshorten())
-  call assert_equal('/f/b/foobar', pathshorten('/foo/bar/foobar'))
-  call assert_equal('.f/bar', pathshorten('.foo/bar'))
-  call assert_equal('~f/bar', pathshorten('~foo/bar'))
-  call assert_equal('~.f/bar', pathshorten('~.foo/bar'))
-  call assert_equal('.~f/bar', pathshorten('.~foo/bar'))
-  call assert_equal('~/f/bar', pathshorten('~/foo/bar'))
-  call assert_fails('call pathshorten([])', 'E730:')
-
-  " test pathshorten with optional variable to set preferred size of shortening
-  call assert_equal('', pathshorten('', 2))
-  call assert_equal('foo', pathshorten('foo', 2))
-  call assert_equal('/foo', pathshorten('/foo', 2))
-  call assert_equal('fo/', pathshorten('foo/', 2))
-  call assert_equal('fo/bar', pathshorten('foo/bar', 2))
-  call assert_equal('fo/ba/foobar', pathshorten('foo/bar/foobar', 2))
-  call assert_equal('/fo/ba/foobar', pathshorten('/foo/bar/foobar', 2))
-  call assert_equal('.fo/bar', pathshorten('.foo/bar', 2))
-  call assert_equal('~fo/bar', pathshorten('~foo/bar', 2))
-  call assert_equal('~.fo/bar', pathshorten('~.foo/bar', 2))
-  call assert_equal('.~fo/bar', pathshorten('.~foo/bar', 2))
-  call assert_equal('~/fo/bar', pathshorten('~/foo/bar', 2))
-  call assert_fails('call pathshorten([],2)', 'E730:')
-  call assert_notequal('~/fo/bar', pathshorten('~/foo/bar', 3))
-  call assert_equal('~/foo/bar', pathshorten('~/foo/bar', 3))
-  call assert_equal('~/f/bar', pathshorten('~/foo/bar', 0))
-endfunc
-
-func Test_strpart()
-  call assert_equal('de', strpart('abcdefg', 3, 2))
-  call assert_equal('ab', strpart('abcdefg', -2, 4))
-  call assert_equal('abcdefg', 'abcdefg'->strpart(-2))
-  call assert_equal('fg', strpart('abcdefg', 5, 4))
-  call assert_equal('defg', strpart('abcdefg', 3))
-  call assert_equal('', strpart('abcdefg', 10))
-  call assert_fails("let s=strpart('abcdef', [])", 'E745:')
-
-  call assert_equal('lép', strpart('éléphant', 2, 4))
-  call assert_equal('léphant', strpart('éléphant', 2))
-
-  call assert_equal('é', strpart('éléphant', 0, 1, 1))
-  call assert_equal('ép', strpart('éléphant', 3, 2, v:true))
-  call assert_equal('ó', strpart('cómposed', 1, 1, 1))
-endfunc
-
-func Test_tolower()
-  call assert_equal("", tolower(""))
-
-  " Test with all printable ASCII characters.
-  call assert_equal(' !"#$%&''()*+,-./0123456789:;<=>?@abcdefghijklmnopqrstuvwxyz[\]^_`abcdefghijklmnopqrstuvwxyz{|}~',
-          \ tolower(' !"#$%&''()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~'))
-
-  " Test with a few uppercase diacritics.
-  call assert_equal("aàáâãäåāăąǎǟǡả", tolower("AÀÁÂÃÄÅĀĂĄǍǞǠẢ"))
-  call assert_equal("bḃḇ", tolower("BḂḆ"))
-  call assert_equal("cçćĉċč", tolower("CÇĆĈĊČ"))
-  call assert_equal("dďđḋḏḑ", tolower("DĎĐḊḎḐ"))
-  call assert_equal("eèéêëēĕėęěẻẽ", tolower("EÈÉÊËĒĔĖĘĚẺẼ"))
-  call assert_equal("fḟ ", tolower("FḞ "))
-  call assert_equal("gĝğġģǥǧǵḡ", tolower("GĜĞĠĢǤǦǴḠ"))
-  call assert_equal("hĥħḣḧḩ", tolower("HĤĦḢḦḨ"))
-  call assert_equal("iìíîïĩīĭįiǐỉ", tolower("IÌÍÎÏĨĪĬĮİǏỈ"))
-  call assert_equal("jĵ", tolower("JĴ"))
-  call assert_equal("kķǩḱḵ", tolower("KĶǨḰḴ"))
-  call assert_equal("lĺļľŀłḻ", tolower("LĹĻĽĿŁḺ"))
-  call assert_equal("mḿṁ", tolower("MḾṀ"))
-  call assert_equal("nñńņňṅṉ", tolower("NÑŃŅŇṄṈ"))
-  call assert_equal("oòóôõöøōŏőơǒǫǭỏ", tolower("OÒÓÔÕÖØŌŎŐƠǑǪǬỎ"))
-  call assert_equal("pṕṗ", tolower("PṔṖ"))
-  call assert_equal("q", tolower("Q"))
-  call assert_equal("rŕŗřṙṟ", tolower("RŔŖŘṘṞ"))
-  call assert_equal("sśŝşšṡ", tolower("SŚŜŞŠṠ"))
-  call assert_equal("tţťŧṫṯ", tolower("TŢŤŦṪṮ"))
-  call assert_equal("uùúûüũūŭůűųưǔủ", tolower("UÙÚÛÜŨŪŬŮŰŲƯǓỦ"))
-  call assert_equal("vṽ", tolower("VṼ"))
-  call assert_equal("wŵẁẃẅẇ", tolower("WŴẀẂẄẆ"))
-  call assert_equal("xẋẍ", tolower("XẊẌ"))
-  call assert_equal("yýŷÿẏỳỷỹ", tolower("YÝŶŸẎỲỶỸ"))
-  call assert_equal("zźżžƶẑẕ", tolower("ZŹŻŽƵẐẔ"))
-
-  " Test with a few lowercase diacritics, which should remain unchanged.
-  call assert_equal("aàáâãäåāăąǎǟǡả", tolower("aàáâãäåāăąǎǟǡả"))
-  call assert_equal("bḃḇ", tolower("bḃḇ"))
-  call assert_equal("cçćĉċč", tolower("cçćĉċč"))
-  call assert_equal("dďđḋḏḑ", tolower("dďđḋḏḑ"))
-  call assert_equal("eèéêëēĕėęěẻẽ", tolower("eèéêëēĕėęěẻẽ"))
-  call assert_equal("fḟ", tolower("fḟ"))
-  call assert_equal("gĝğġģǥǧǵḡ", tolower("gĝğġģǥǧǵḡ"))
-  call assert_equal("hĥħḣḧḩẖ", tolower("hĥħḣḧḩẖ"))
-  call assert_equal("iìíîïĩīĭįǐỉ", tolower("iìíîïĩīĭįǐỉ"))
-  call assert_equal("jĵǰ", tolower("jĵǰ"))
-  call assert_equal("kķǩḱḵ", tolower("kķǩḱḵ"))
-  call assert_equal("lĺļľŀłḻ", tolower("lĺļľŀłḻ"))
-  call assert_equal("mḿṁ ", tolower("mḿṁ "))
-  call assert_equal("nñńņňʼnṅṉ", tolower("nñńņňʼnṅṉ"))
-  call assert_equal("oòóôõöøōŏőơǒǫǭỏ", tolower("oòóôõöøōŏőơǒǫǭỏ"))
-  call assert_equal("pṕṗ", tolower("pṕṗ"))
-  call assert_equal("q", tolower("q"))
-  call assert_equal("rŕŗřṙṟ", tolower("rŕŗřṙṟ"))
-  call assert_equal("sśŝşšṡ", tolower("sśŝşšṡ"))
-  call assert_equal("tţťŧṫṯẗ", tolower("tţťŧṫṯẗ"))
-  call assert_equal("uùúûüũūŭůűųưǔủ", tolower("uùúûüũūŭůűųưǔủ"))
-  call assert_equal("vṽ", tolower("vṽ"))
-  call assert_equal("wŵẁẃẅẇẘ", tolower("wŵẁẃẅẇẘ"))
-  call assert_equal("ẋẍ", tolower("ẋẍ"))
-  call assert_equal("yýÿŷẏẙỳỷỹ", tolower("yýÿŷẏẙỳỷỹ"))
-  call assert_equal("zźżžƶẑẕ", tolower("zźżžƶẑẕ"))
-
-  " According to https://twitter.com/jifa/status/625776454479970304
-  " Ⱥ (U+023A) and Ⱦ (U+023E) are the *only* code points to increase
-  " in length (2 to 3 bytes) when lowercased. So let's test them.
-  call assert_equal("ⱥ ⱦ", tolower("Ⱥ Ⱦ"))
-
-  " This call to tolower with invalid utf8 sequence used to cause access to
-  " invalid memory.
-  call tolower("\xC0\x80\xC0")
-  call tolower("123\xC0\x80\xC0")
-
-  " Test in latin1 encoding
-  let save_enc = &encoding
-  set encoding=latin1
-  call assert_equal("abc", tolower("ABC"))
-  let &encoding = save_enc
-endfunc
-
-func Test_toupper()
-  call assert_equal("", toupper(""))
-
-  " Test with all printable ASCII characters.
-  call assert_equal(' !"#$%&''()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`ABCDEFGHIJKLMNOPQRSTUVWXYZ{|}~',
-          \ toupper(' !"#$%&''()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~'))
-
-  " Test with a few lowercase diacritics.
-  call assert_equal("AÀÁÂÃÄÅĀĂĄǍǞǠẢ", "aàáâãäåāăąǎǟǡả"->toupper())
-  call assert_equal("BḂḆ", toupper("bḃḇ"))
-  call assert_equal("CÇĆĈĊČ", toupper("cçćĉċč"))
-  call assert_equal("DĎĐḊḎḐ", toupper("dďđḋḏḑ"))
-  call assert_equal("EÈÉÊËĒĔĖĘĚẺẼ", toupper("eèéêëēĕėęěẻẽ"))
-  call assert_equal("FḞ", toupper("fḟ"))
-  call assert_equal("GĜĞĠĢǤǦǴḠ", toupper("gĝğġģǥǧǵḡ"))
-  call assert_equal("HĤĦḢḦḨẖ", toupper("hĥħḣḧḩẖ"))
-  call assert_equal("IÌÍÎÏĨĪĬĮǏỈ", toupper("iìíîïĩīĭįǐỉ"))
-  call assert_equal("JĴǰ", toupper("jĵǰ"))
-  call assert_equal("KĶǨḰḴ", toupper("kķǩḱḵ"))
-  call assert_equal("LĹĻĽĿŁḺ", toupper("lĺļľŀłḻ"))
-  call assert_equal("MḾṀ ", toupper("mḿṁ "))
-  call assert_equal("NÑŃŅŇʼnṄṈ", toupper("nñńņňʼnṅṉ"))
-  call assert_equal("OÒÓÔÕÖØŌŎŐƠǑǪǬỎ", toupper("oòóôõöøōŏőơǒǫǭỏ"))
-  call assert_equal("PṔṖ", toupper("pṕṗ"))
-  call assert_equal("Q", toupper("q"))
-  call assert_equal("RŔŖŘṘṞ", toupper("rŕŗřṙṟ"))
-  call assert_equal("SŚŜŞŠṠ", toupper("sśŝşšṡ"))
-  call assert_equal("TŢŤŦṪṮẗ", toupper("tţťŧṫṯẗ"))
-  call assert_equal("UÙÚÛÜŨŪŬŮŰŲƯǓỦ", toupper("uùúûüũūŭůűųưǔủ"))
-  call assert_equal("VṼ", toupper("vṽ"))
-  call assert_equal("WŴẀẂẄẆẘ", toupper("wŵẁẃẅẇẘ"))
-  call assert_equal("ẊẌ", toupper("ẋẍ"))
-  call assert_equal("YÝŸŶẎẙỲỶỸ", toupper("yýÿŷẏẙỳỷỹ"))
-  call assert_equal("ZŹŻŽƵẐẔ", toupper("zźżžƶẑẕ"))
-
-  " Test that uppercase diacritics, which should remain unchanged.
-  call assert_equal("AÀÁÂÃÄÅĀĂĄǍǞǠẢ", toupper("AÀÁÂÃÄÅĀĂĄǍǞǠẢ"))
-  call assert_equal("BḂḆ", toupper("BḂḆ"))
-  call assert_equal("CÇĆĈĊČ", toupper("CÇĆĈĊČ"))
-  call assert_equal("DĎĐḊḎḐ", toupper("DĎĐḊḎḐ"))
-  call assert_equal("EÈÉÊËĒĔĖĘĚẺẼ", toupper("EÈÉÊËĒĔĖĘĚẺẼ"))
-  call assert_equal("FḞ ", toupper("FḞ "))
-  call assert_equal("GĜĞĠĢǤǦǴḠ", toupper("GĜĞĠĢǤǦǴḠ"))
-  call assert_equal("HĤĦḢḦḨ", toupper("HĤĦḢḦḨ"))
-  call assert_equal("IÌÍÎÏĨĪĬĮİǏỈ", toupper("IÌÍÎÏĨĪĬĮİǏỈ"))
-  call assert_equal("JĴ", toupper("JĴ"))
-  call assert_equal("KĶǨḰḴ", toupper("KĶǨḰḴ"))
-  call assert_equal("LĹĻĽĿŁḺ", toupper("LĹĻĽĿŁḺ"))
-  call assert_equal("MḾṀ", toupper("MḾṀ"))
-  call assert_equal("NÑŃŅŇṄṈ", toupper("NÑŃŅŇṄṈ"))
-  call assert_equal("OÒÓÔÕÖØŌŎŐƠǑǪǬỎ", toupper("OÒÓÔÕÖØŌŎŐƠǑǪǬỎ"))
-  call assert_equal("PṔṖ", toupper("PṔṖ"))
-  call assert_equal("Q", toupper("Q"))
-  call assert_equal("RŔŖŘṘṞ", toupper("RŔŖŘṘṞ"))
-  call assert_equal("SŚŜŞŠṠ", toupper("SŚŜŞŠṠ"))
-  call assert_equal("TŢŤŦṪṮ", toupper("TŢŤŦṪṮ"))
-  call assert_equal("UÙÚÛÜŨŪŬŮŰŲƯǓỦ", toupper("UÙÚÛÜŨŪŬŮŰŲƯǓỦ"))
-  call assert_equal("VṼ", toupper("VṼ"))
-  call assert_equal("WŴẀẂẄẆ", toupper("WŴẀẂẄẆ"))
-  call assert_equal("XẊẌ", toupper("XẊẌ"))
-  call assert_equal("YÝŶŸẎỲỶỸ", toupper("YÝŶŸẎỲỶỸ"))
-  call assert_equal("ZŹŻŽƵẐẔ", toupper("ZŹŻŽƵẐẔ"))
-
-  call assert_equal("Ⱥ Ⱦ", toupper("ⱥ ⱦ"))
-
-  " This call to toupper with invalid utf8 sequence used to cause access to
-  " invalid memory.
-  call toupper("\xC0\x80\xC0")
-  call toupper("123\xC0\x80\xC0")
-
-  " Test in latin1 encoding
-  let save_enc = &encoding
-  set encoding=latin1
-  call assert_equal("ABC", toupper("abc"))
-  let &encoding = save_enc
-endfunc
-
-func Test_tr()
-  call assert_equal('foo', tr('bar', 'bar', 'foo'))
-  call assert_equal('zxy', 'cab'->tr('abc', 'xyz'))
-  call assert_fails("let s=tr([], 'abc', 'def')", 'E730:')
-  call assert_fails("let s=tr('abc', [], 'def')", 'E730:')
-  call assert_fails("let s=tr('abc', 'abc', [])", 'E730:')
-  call assert_fails("let s=tr('abcd', 'abcd', 'def')", 'E475:')
-  set encoding=latin1
-  call assert_fails("let s=tr('abcd', 'abcd', 'def')", 'E475:')
-  call assert_equal('hEllO', tr('hello', 'eo', 'EO'))
-  call assert_equal('hello', tr('hello', 'xy', 'ab'))
-  call assert_fails('call tr("abc", "123", "₁₂")', 'E475:')
-  set encoding=utf8
-endfunc
-
-" Tests for the mode() function
-let current_modes = ''
-func Save_mode()
-  let g:current_modes = mode(0) . '-' . mode(1)
-  return ''
-endfunc
-
-" Test for the mode() function
-func Test_mode()
-  new
-  call append(0, ["Blue Ball Black", "Brown Band Bowl", ""])
-
-  " Only complete from the current buffer.
-  set complete=.
-
-  inoremap <F2> <C-R>=Save_mode()<CR>
-  xnoremap <F2> <Cmd>call Save_mode()<CR>
-
-  normal! 3G
-  exe "normal i\<F2>\<Esc>"
-  call assert_equal('i-i', g:current_modes)
-  " i_CTRL-P: Multiple matches
-  exe "normal i\<C-G>uBa\<C-P>\<F2>\<Esc>u"
-  call assert_equal('i-ic', g:current_modes)
-  " i_CTRL-P: Single match
-  exe "normal iBro\<C-P>\<F2>\<Esc>u"
-  call assert_equal('i-ic', g:current_modes)
-  " i_CTRL-X
-  exe "normal iBa\<C-X>\<F2>\<Esc>u"
-  call assert_equal('i-ix', g:current_modes)
-  " i_CTRL-X CTRL-P: Multiple matches
-  exe "normal iBa\<C-X>\<C-P>\<F2>\<Esc>u"
-  call assert_equal('i-ic', g:current_modes)
-  " i_CTRL-X CTRL-P: Single match
-  exe "normal iBro\<C-X>\<C-P>\<F2>\<Esc>u"
-  call assert_equal('i-ic', g:current_modes)
-  " i_CTRL-X CTRL-P + CTRL-P: Single match
-  exe "normal iBro\<C-X>\<C-P>\<C-P>\<F2>\<Esc>u"
-  call assert_equal('i-ic', g:current_modes)
-  " i_CTRL-X CTRL-L: Multiple matches
-  exe "normal i\<C-X>\<C-L>\<F2>\<Esc>u"
-  call assert_equal('i-ic', g:current_modes)
-  " i_CTRL-X CTRL-L: Single match
-  exe "normal iBlu\<C-X>\<C-L>\<F2>\<Esc>u"
-  call assert_equal('i-ic', g:current_modes)
-  " i_CTRL-P: No match
-  exe "normal iCom\<C-P>\<F2>\<Esc>u"
-  call assert_equal('i-ic', g:current_modes)
-  " i_CTRL-X CTRL-P: No match
-  exe "normal iCom\<C-X>\<C-P>\<F2>\<Esc>u"
-  call assert_equal('i-ic', g:current_modes)
-  " i_CTRL-X CTRL-L: No match
-  exe "normal iabc\<C-X>\<C-L>\<F2>\<Esc>u"
-  call assert_equal('i-ic', g:current_modes)
-
-  exe "normal R\<F2>\<Esc>"
-  call assert_equal('R-R', g:current_modes)
-  " R_CTRL-P: Multiple matches
-  exe "normal RBa\<C-P>\<F2>\<Esc>u"
-  call assert_equal('R-Rc', g:current_modes)
-  " R_CTRL-P: Single match
-  exe "normal RBro\<C-P>\<F2>\<Esc>u"
-  call assert_equal('R-Rc', g:current_modes)
-  " R_CTRL-X
-  exe "normal RBa\<C-X>\<F2>\<Esc>u"
-  call assert_equal('R-Rx', g:current_modes)
-  " R_CTRL-X CTRL-P: Multiple matches
-  exe "normal RBa\<C-X>\<C-P>\<F2>\<Esc>u"
-  call assert_equal('R-Rc', g:current_modes)
-  " R_CTRL-X CTRL-P: Single match
-  exe "normal RBro\<C-X>\<C-P>\<F2>\<Esc>u"
-  call assert_equal('R-Rc', g:current_modes)
-  " R_CTRL-X CTRL-P + CTRL-P: Single match
-  exe "normal RBro\<C-X>\<C-P>\<C-P>\<F2>\<Esc>u"
-  call assert_equal('R-Rc', g:current_modes)
-  " R_CTRL-X CTRL-L: Multiple matches
-  exe "normal R\<C-X>\<C-L>\<F2>\<Esc>u"
-  call assert_equal('R-Rc', g:current_modes)
-  " R_CTRL-X CTRL-L: Single match
-  exe "normal RBlu\<C-X>\<C-L>\<F2>\<Esc>u"
-  call assert_equal('R-Rc', g:current_modes)
-  " R_CTRL-P: No match
-  exe "normal RCom\<C-P>\<F2>\<Esc>u"
-  call assert_equal('R-Rc', g:current_modes)
-  " R_CTRL-X CTRL-P: No match
-  exe "normal RCom\<C-X>\<C-P>\<F2>\<Esc>u"
-  call assert_equal('R-Rc', g:current_modes)
-  " R_CTRL-X CTRL-L: No match
-  exe "normal Rabc\<C-X>\<C-L>\<F2>\<Esc>u"
-  call assert_equal('R-Rc', g:current_modes)
-
-  exe "normal gR\<F2>\<Esc>"
-  call assert_equal('R-Rv', g:current_modes)
-  " gR_CTRL-P: Multiple matches
-  exe "normal gRBa\<C-P>\<F2>\<Esc>u"
-  call assert_equal('R-Rvc', g:current_modes)
-  " gR_CTRL-P: Single match
-  exe "normal gRBro\<C-P>\<F2>\<Esc>u"
-  call assert_equal('R-Rvc', g:current_modes)
-  " gR_CTRL-X
-  exe "normal gRBa\<C-X>\<F2>\<Esc>u"
-  call assert_equal('R-Rvx', g:current_modes)
-  " gR_CTRL-X CTRL-P: Multiple matches
-  exe "normal gRBa\<C-X>\<C-P>\<F2>\<Esc>u"
-  call assert_equal('R-Rvc', g:current_modes)
-  " gR_CTRL-X CTRL-P: Single match
-  exe "normal gRBro\<C-X>\<C-P>\<F2>\<Esc>u"
-  call assert_equal('R-Rvc', g:current_modes)
-  " gR_CTRL-X CTRL-P + CTRL-P: Single match
-  exe "normal gRBro\<C-X>\<C-P>\<C-P>\<F2>\<Esc>u"
-  call assert_equal('R-Rvc', g:current_modes)
-  " gR_CTRL-X CTRL-L: Multiple matches
-  exe "normal gR\<C-X>\<C-L>\<F2>\<Esc>u"
-  call assert_equal('R-Rvc', g:current_modes)
-  " gR_CTRL-X CTRL-L: Single match
-  exe "normal gRBlu\<C-X>\<C-L>\<F2>\<Esc>u"
-  call assert_equal('R-Rvc', g:current_modes)
-  " gR_CTRL-P: No match
-  exe "normal gRCom\<C-P>\<F2>\<Esc>u"
-  call assert_equal('R-Rvc', g:current_modes)
-  " gR_CTRL-X CTRL-P: No match
-  exe "normal gRCom\<C-X>\<C-P>\<F2>\<Esc>u"
-  call assert_equal('R-Rvc', g:current_modes)
-  " gR_CTRL-X CTRL-L: No match
-  exe "normal gRabc\<C-X>\<C-L>\<F2>\<Esc>u"
-  call assert_equal('R-Rvc', g:current_modes)
-
-  call assert_equal('n', 0->mode())
-  call assert_equal('n', 1->mode())
-
-  " i_CTRL-O
-  exe "normal i\<C-O>:call Save_mode()\<Cr>\<Esc>"
-  call assert_equal("n-niI", g:current_modes)
-
-  " R_CTRL-O
-  exe "normal R\<C-O>:call Save_mode()\<Cr>\<Esc>"
-  call assert_equal("n-niR", g:current_modes)
-
-  " gR_CTRL-O
-  exe "normal gR\<C-O>:call Save_mode()\<Cr>\<Esc>"
-  call assert_equal("n-niV", g:current_modes)
-
-  " How to test operator-pending mode?
-
-  call feedkeys("v", 'xt')
-  call assert_equal('v', mode())
-  call assert_equal('v', mode(1))
-  call feedkeys("\<Esc>V", 'xt')
-  call assert_equal('V', mode())
-  call assert_equal('V', mode(1))
-  call feedkeys("\<Esc>\<C-V>", 'xt')
-  call assert_equal("\<C-V>", mode())
-  call assert_equal("\<C-V>", mode(1))
-  call feedkeys("\<Esc>", 'xt')
-
-  call feedkeys("gh", 'xt')
-  call assert_equal('s', mode())
-  call assert_equal('s', mode(1))
-  call feedkeys("\<Esc>gH", 'xt')
-  call assert_equal('S', mode())
-  call assert_equal('S', mode(1))
-  call feedkeys("\<Esc>g\<C-H>", 'xt')
-  call assert_equal("\<C-S>", mode())
-  call assert_equal("\<C-S>", mode(1))
-  call feedkeys("\<Esc>", 'xt')
-
-  " v_CTRL-O
-  exe "normal gh\<C-O>\<F2>\<Esc>"
-  call assert_equal("v-vs", g:current_modes)
-  exe "normal gH\<C-O>\<F2>\<Esc>"
-  call assert_equal("V-Vs", g:current_modes)
-  exe "normal g\<C-H>\<C-O>\<F2>\<Esc>"
-  call assert_equal("\<C-V>-\<C-V>s", g:current_modes)
-
-  call feedkeys(":echo \<C-R>=Save_mode()\<C-U>\<CR>", 'xt')
-  call assert_equal('c-c', g:current_modes)
-  call feedkeys("gQecho \<C-R>=Save_mode()\<CR>\<CR>vi\<CR>", 'xt')
-  call assert_equal('c-cv', g:current_modes)
-  call feedkeys("Qcall Save_mode()\<CR>vi\<CR>", 'xt')
-  call assert_equal('c-ce', g:current_modes)
-  " How to test Ex mode?
-
-  " Test mode in operatorfunc (it used to be Operator-pending).
-  set operatorfunc=OperatorFunc
-  function OperatorFunc(_)
-    call Save_mode()
-  endfunction
-  execute "normal! g@l\<Esc>"
-  call assert_equal('n-n', g:current_modes)
-  execute "normal! i\<C-o>g@l\<Esc>"
-  call assert_equal('n-niI', g:current_modes)
-  execute "normal! R\<C-o>g@l\<Esc>"
-  call assert_equal('n-niR', g:current_modes)
-  execute "normal! gR\<C-o>g@l\<Esc>"
-  call assert_equal('n-niV', g:current_modes)
-
-  if has('terminal')
-    term
-    call feedkeys("\<C-W>N", 'xt')
-    call assert_equal('n', mode())
-    call assert_equal('nt', mode(1))
-    call feedkeys("aexit\<CR>", 'xt')
-  endif
-
-  bwipe!
-  iunmap <F2>
-  xunmap <F2>
-  set complete&
-  set operatorfunc&
-  delfunction OperatorFunc
-endfunc
-
-" Test for append()
-func Test_append()
-  enew!
-  split
-  call assert_equal(0, append(1, []))
-  call assert_equal(0, append(1, test_null_list()))
-  call assert_equal(0, append(0, ["foo"]))
-  call assert_equal(0, append(1, []))
-  call assert_equal(0, append(1, test_null_list()))
-  call assert_equal(0, append(8, []))
-  call assert_equal(0, append(9, test_null_list()))
-  call assert_equal(['foo', ''], getline(1, '$'))
-  split
-  only
-  undo
-  undo
-
-  " Using $ instead of '$' must give an error
-  call assert_fails("call append($, 'foobar')", 'E116:')
-
-  call assert_fails("call append({}, '')", ['E728:', 'E728:'])
-endfunc
-
-" Test for setline()
-func Test_setline()
-  new
-  call setline(0, ["foo"])
-  call setline(0, [])
-  call setline(0, test_null_list())
-  call setline(1, ["bar"])
-  call setline(1, [])
-  call setline(1, test_null_list())
-  call setline(2, [])
-  call setline(2, test_null_list())
-  call setline(3, [])
-  call setline(3, test_null_list())
-  call setline(2, ["baz"])
-  call assert_equal(['bar', 'baz'], getline(1, '$'))
-  close!
-endfunc
-
-func Test_getbufvar()
-  let bnr = bufnr('%')
-  let b:var_num = '1234'
-  let def_num = '5678'
-  call assert_equal('1234', getbufvar(bnr, 'var_num'))
-  call assert_equal('1234', getbufvar(bnr, 'var_num', def_num))
-
-  let bd = getbufvar(bnr, '')
-  call assert_equal('1234', bd['var_num'])
-  call assert_true(exists("bd['changedtick']"))
-  call assert_equal(2, len(bd))
-
-  let bd2 = getbufvar(bnr, '', def_num)
-  call assert_equal(bd, bd2)
-
-  unlet b:var_num
-  call assert_equal(def_num, getbufvar(bnr, 'var_num', def_num))
-  call assert_equal('', getbufvar(bnr, 'var_num'))
-
-  let bd = getbufvar(bnr, '')
-  call assert_equal(1, len(bd))
-  let bd = getbufvar(bnr, '',def_num)
-  call assert_equal(1, len(bd))
-
-  call assert_equal('', getbufvar(9999, ''))
-  call assert_equal(def_num, getbufvar(9999, '', def_num))
-  unlet def_num
-
-  call assert_equal(0, getbufvar(bnr, '&autoindent'))
-  call assert_equal(0, getbufvar(bnr, '&autoindent', 1))
-
-  " Set and get a buffer-local variable
-  call setbufvar(bnr, 'bufvar_test', ['one', 'two'])
-  call assert_equal(['one', 'two'], getbufvar(bnr, 'bufvar_test'))
-
-  " Open new window with forced option values
-  set fileformats=unix,dos
-  new ++ff=dos ++bin ++enc=iso-8859-2
-  call assert_equal('dos', getbufvar(bufnr('%'), '&fileformat'))
-  call assert_equal(1, getbufvar(bufnr('%'), '&bin'))
-  call assert_equal('iso-8859-2', getbufvar(bufnr('%'), '&fenc'))
-  close
-
-  " Get the b: dict.
-  let b:testvar = 'one'
-  new
-  let b:testvar = 'two'
-  let thebuf = bufnr()
-  wincmd w
-  call assert_equal('two', getbufvar(thebuf, 'testvar'))
-  call assert_equal('two', getbufvar(thebuf, '').testvar)
-  bwipe!
-
-  set fileformats&
-endfunc
-
-func Test_last_buffer_nr()
-  call assert_equal(bufnr('$'), last_buffer_nr())
-endfunc
-
-func Test_stridx()
-  call assert_equal(-1, stridx('', 'l'))
-  call assert_equal(0,  stridx('', ''))
-  call assert_equal(0,  'hello'->stridx(''))
-  call assert_equal(-1, stridx('hello', 'L'))
-  call assert_equal(2,  stridx('hello', 'l', -1))
-  call assert_equal(2,  stridx('hello', 'l', 0))
-  call assert_equal(2,  'hello'->stridx('l', 1))
-  call assert_equal(3,  stridx('hello', 'l', 3))
-  call assert_equal(-1, stridx('hello', 'l', 4))
-  call assert_equal(-1, stridx('hello', 'l', 10))
-  call assert_equal(2,  stridx('hello', 'll'))
-  call assert_equal(-1, stridx('hello', 'hello world'))
-  call assert_fails("let n=stridx('hello', [])", 'E730:')
-  call assert_fails("let n=stridx([], 'l')", 'E730:')
-endfunc
-
-func Test_strridx()
-  call assert_equal(-1, strridx('', 'l'))
-  call assert_equal(0,  strridx('', ''))
-  call assert_equal(5,  strridx('hello', ''))
-  call assert_equal(-1, strridx('hello', 'L'))
-  call assert_equal(3,  'hello'->strridx('l'))
-  call assert_equal(3,  strridx('hello', 'l', 10))
-  call assert_equal(3,  strridx('hello', 'l', 3))
-  call assert_equal(2,  strridx('hello', 'l', 2))
-  call assert_equal(-1, strridx('hello', 'l', 1))
-  call assert_equal(-1, strridx('hello', 'l', 0))
-  call assert_equal(-1, strridx('hello', 'l', -1))
-  call assert_equal(2,  strridx('hello', 'll'))
-  call assert_equal(-1, strridx('hello', 'hello world'))
-  call assert_fails("let n=strridx('hello', [])", 'E730:')
-  call assert_fails("let n=strridx([], 'l')", 'E730:')
-endfunc
-
-func Test_match_func()
-  call assert_equal(4,  match('testing', 'ing'))
-  call assert_equal(4,  'testing'->match('ing', 2))
-  call assert_equal(-1, match('testing', 'ing', 5))
-  call assert_equal(-1, match('testing', 'ing', 8))
-  call assert_equal(1, match(['vim', 'testing', 'execute'], 'ing'))
-  call assert_equal(-1, match(['vim', 'testing', 'execute'], 'img'))
-  call assert_fails("let x=match('vim', [])", 'E730:')
-  call assert_equal(3, match(['a', 'b', 'c', 'a'], 'a', 1))
-  call assert_equal(-1, match(['a', 'b', 'c', 'a'], 'a', 5))
-  call assert_equal(4,  match('testing', 'ing', -1))
-  call assert_fails("let x=match('testing', 'ing', 0, [])", 'E745:')
-  call assert_equal(-1, match(test_null_list(), 2))
-  call assert_equal(-1, match('abc', '\\%('))
-endfunc
-
-func Test_matchend()
-  call assert_equal(7,  matchend('testing', 'ing'))
-  call assert_equal(7,  'testing'->matchend('ing', 2))
-  call assert_equal(-1, matchend('testing', 'ing', 5))
-  call assert_equal(-1, matchend('testing', 'ing', 8))
-  call assert_equal(match(['vim', 'testing', 'execute'], 'ing'), matchend(['vim', 'testing', 'execute'], 'ing'))
-  call assert_equal(match(['vim', 'testing', 'execute'], 'img'), matchend(['vim', 'testing', 'execute'], 'img'))
-endfunc
-
-func Test_matchlist()
-  call assert_equal(['acd', 'a', '', 'c', 'd', '', '', '', '', ''],  matchlist('acd', '\(a\)\?\(b\)\?\(c\)\?\(.*\)'))
-  call assert_equal(['d', '', '', '', 'd', '', '', '', '', ''],  'acd'->matchlist('\(a\)\?\(b\)\?\(c\)\?\(.*\)', 2))
-  call assert_equal([],  matchlist('acd', '\(a\)\?\(b\)\?\(c\)\?\(.*\)', 4))
-endfunc
-
-func Test_matchstr()
-  call assert_equal('ing',  matchstr('testing', 'ing'))
-  call assert_equal('ing',  'testing'->matchstr('ing', 2))
-  call assert_equal('', matchstr('testing', 'ing', 5))
-  call assert_equal('', matchstr('testing', 'ing', 8))
-  call assert_equal('testing', matchstr(['vim', 'testing', 'execute'], 'ing'))
-  call assert_equal('', matchstr(['vim', 'testing', 'execute'], 'img'))
-endfunc
-
-func Test_matchstrpos()
-  call assert_equal(['ing', 4, 7], matchstrpos('testing', 'ing'))
-  call assert_equal(['ing', 4, 7], 'testing'->matchstrpos('ing', 2))
-  call assert_equal(['', -1, -1], matchstrpos('testing', 'ing', 5))
-  call assert_equal(['', -1, -1], matchstrpos('testing', 'ing', 8))
-  call assert_equal(['ing', 1, 4, 7], matchstrpos(['vim', 'testing', 'execute'], 'ing'))
-  call assert_equal(['', -1, -1, -1], matchstrpos(['vim', 'testing', 'execute'], 'img'))
-  call assert_equal(['', -1, -1], matchstrpos(test_null_list(), '\a'))
-endfunc
-
-func Test_nextnonblank_prevnonblank()
-  new
-insert
-This
-
-
-is
-
-a
-Test
-.
-  call assert_equal(0, nextnonblank(-1))
-  call assert_equal(0, nextnonblank(0))
-  call assert_equal(1, nextnonblank(1))
-  call assert_equal(4, 2->nextnonblank())
-  call assert_equal(4, nextnonblank(3))
-  call assert_equal(4, nextnonblank(4))
-  call assert_equal(6, nextnonblank(5))
-  call assert_equal(6, nextnonblank(6))
-  call assert_equal(7, nextnonblank(7))
-  call assert_equal(0, 8->nextnonblank())
-
-  call assert_equal(0, prevnonblank(-1))
-  call assert_equal(0, prevnonblank(0))
-  call assert_equal(1, 1->prevnonblank())
-  call assert_equal(1, prevnonblank(2))
-  call assert_equal(1, prevnonblank(3))
-  call assert_equal(4, prevnonblank(4))
-  call assert_equal(4, 5->prevnonblank())
-  call assert_equal(6, prevnonblank(6))
-  call assert_equal(7, prevnonblank(7))
-  call assert_equal(0, prevnonblank(8))
-  bw!
-endfunc
-
-func Test_byte2line_line2byte()
-  new
-  set endofline
-  call setline(1, ['a', 'bc', 'd'])
-
-  set fileformat=unix
-  call assert_equal([-1, -1, 1, 1, 2, 2, 2, 3, 3, -1],
-  \                 map(range(-1, 8), 'byte2line(v:val)'))
-  call assert_equal([-1, -1, 1, 3, 6, 8, -1],
-  \                 map(range(-1, 5), 'line2byte(v:val)'))
-
-  set fileformat=mac
-  call assert_equal([-1, -1, 1, 1, 2, 2, 2, 3, 3, -1],
-  \                 map(range(-1, 8), 'v:val->byte2line()'))
-  call assert_equal([-1, -1, 1, 3, 6, 8, -1],
-  \                 map(range(-1, 5), 'v:val->line2byte()'))
-
-  set fileformat=dos
-  call assert_equal([-1, -1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, -1],
-  \                 map(range(-1, 11), 'byte2line(v:val)'))
-  call assert_equal([-1, -1, 1, 4, 8, 11, -1],
-  \                 map(range(-1, 5), 'line2byte(v:val)'))
-
-  bw!
-  set noendofline nofixendofline
-  normal a-
-  for ff in ["unix", "mac", "dos"]
-    let &fileformat = ff
-    call assert_equal(1, line2byte(1))
-    call assert_equal(2, line2byte(2))  " line2byte(line("$") + 1) is the buffer size plus one (as per :help line2byte).
-  endfor
-
-  set endofline& fixendofline& fileformat&
-  bw!
-endfunc
-
-" Test for byteidx() using a character index
-func Test_byteidx()
-  let a = '.é.' " one char of two bytes
-  call assert_equal(0, byteidx(a, 0))
-  call assert_equal(1, byteidx(a, 1))
-  call assert_equal(3, byteidx(a, 2))
-  call assert_equal(4, byteidx(a, 3))
-  call assert_equal(-1, byteidx(a, 4))
-
-  let b = '.é.' " normal e with composing char
-  call assert_equal(0, b->byteidx(0))
-  call assert_equal(1, b->byteidx(1))
-  call assert_equal(4, b->byteidx(2))
-  call assert_equal(5, b->byteidx(3))
-  call assert_equal(-1, b->byteidx(4))
-
-  " string with multiple composing characters
-  let str = '-ą́-ą́'
-  call assert_equal(0, byteidx(str, 0))
-  call assert_equal(1, byteidx(str, 1))
-  call assert_equal(6, byteidx(str, 2))
-  call assert_equal(7, byteidx(str, 3))
-  call assert_equal(12, byteidx(str, 4))
-  call assert_equal(-1, byteidx(str, 5))
-
-  " empty string
-  call assert_equal(0, byteidx('', 0))
-  call assert_equal(-1, byteidx('', 1))
-
-  " error cases
-  call assert_fails("call byteidx([], 0)", 'E730:')
-  call assert_fails("call byteidx('abc', [])", 'E745:')
-  call assert_fails("call byteidx('abc', 0, {})", ['E728:', 'E728:'])
-  call assert_fails("call byteidx('abc', 0, -1)", ['E1023:', 'E1023:'])
-endfunc
-
-" Test for byteidxcomp() using a character index
-func Test_byteidxcomp()
-  let a = '.é.' " one char of two bytes
-  call assert_equal(0, byteidxcomp(a, 0))
-  call assert_equal(1, byteidxcomp(a, 1))
-  call assert_equal(3, byteidxcomp(a, 2))
-  call assert_equal(4, byteidxcomp(a, 3))
-  call assert_equal(-1, byteidxcomp(a, 4))
-
-  let b = '.é.' " normal e with composing char
-  call assert_equal(0, b->byteidxcomp(0))
-  call assert_equal(1, b->byteidxcomp(1))
-  call assert_equal(2, b->byteidxcomp(2))
-  call assert_equal(4, b->byteidxcomp(3))
-  call assert_equal(5, b->byteidxcomp(4))
-  call assert_equal(-1, b->byteidxcomp(5))
-
-  " string with multiple composing characters
-  let str = '-ą́-ą́'
-  call assert_equal(0, byteidxcomp(str, 0))
-  call assert_equal(1, byteidxcomp(str, 1))
-  call assert_equal(2, byteidxcomp(str, 2))
-  call assert_equal(4, byteidxcomp(str, 3))
-  call assert_equal(6, byteidxcomp(str, 4))
-  call assert_equal(7, byteidxcomp(str, 5))
-  call assert_equal(8, byteidxcomp(str, 6))
-  call assert_equal(10, byteidxcomp(str, 7))
-  call assert_equal(12, byteidxcomp(str, 8))
-  call assert_equal(-1, byteidxcomp(str, 9))
-
-  " empty string
-  call assert_equal(0, byteidxcomp('', 0))
-  call assert_equal(-1, byteidxcomp('', 1))
-
-  " error cases
-  call assert_fails("call byteidxcomp([], 0)", 'E730:')
-  call assert_fails("call byteidxcomp('abc', [])", 'E745:')
-  call assert_fails("call byteidxcomp('abc', 0, {})", ['E728:', 'E728:'])
-  call assert_fails("call byteidxcomp('abc', 0, -1)", ['E1023:', 'E1023:'])
-endfunc
-
-" Test for byteidx() using a UTF-16 index
-func Test_byteidx_from_utf16_index()
-  " string with single byte characters
-  let str = "abc"
-  for i in range(3)
-    call assert_equal(i, byteidx(str, i, v:true))
-  endfor
-  call assert_equal(3, byteidx(str, 3, v:true))
-  call assert_equal(-1, byteidx(str, 4, v:true))
-
-  " string with two byte characters
-  let str = "a©©b"
-  call assert_equal(0, byteidx(str, 0, v:true))
-  call assert_equal(1, byteidx(str, 1, v:true))
-  call assert_equal(3, byteidx(str, 2, v:true))
-  call assert_equal(5, byteidx(str, 3, v:true))
-  call assert_equal(6, byteidx(str, 4, v:true))
-  call assert_equal(-1, byteidx(str, 5, v:true))
-
-  " string with two byte characters
-  let str = "a😊😊b"
-  call assert_equal(0, byteidx(str, 0, v:true))
-  call assert_equal(1, byteidx(str, 1, v:true))
-  call assert_equal(1, byteidx(str, 2, v:true))
-  call assert_equal(5, byteidx(str, 3, v:true))
-  call assert_equal(5, byteidx(str, 4, v:true))
-  call assert_equal(9, byteidx(str, 5, v:true))
-  call assert_equal(10, byteidx(str, 6, v:true))
-  call assert_equal(-1, byteidx(str, 7, v:true))
-
-  " string with composing characters
-  let str = '-á-b́'
-  call assert_equal(0, byteidx(str, 0, v:true))
-  call assert_equal(1, byteidx(str, 1, v:true))
-  call assert_equal(4, byteidx(str, 2, v:true))
-  call assert_equal(5, byteidx(str, 3, v:true))
-  call assert_equal(8, byteidx(str, 4, v:true))
-  call assert_equal(-1, byteidx(str, 5, v:true))
-
-  " string with multiple composing characters
-  let str = '-ą́-ą́'
-  call assert_equal(0, byteidx(str, 0, v:true))
-  call assert_equal(1, byteidx(str, 1, v:true))
-  call assert_equal(6, byteidx(str, 2, v:true))
-  call assert_equal(7, byteidx(str, 3, v:true))
-  call assert_equal(12, byteidx(str, 4, v:true))
-  call assert_equal(-1, byteidx(str, 5, v:true))
-
-  " empty string
-  call assert_equal(0, byteidx('', 0, v:true))
-  call assert_equal(-1, byteidx('', 1, v:true))
-
-  " error cases
-  call assert_fails('call byteidx(str, 0, [])', 'E745:')
-endfunc
-
-" Test for byteidxcomp() using a UTF-16 index
-func Test_byteidxcomp_from_utf16_index()
-  " string with single byte characters
-  let str = "abc"
-  for i in range(3)
-    call assert_equal(i, byteidxcomp(str, i, v:true))
-  endfor
-  call assert_equal(3, byteidxcomp(str, 3, v:true))
-  call assert_equal(-1, byteidxcomp(str, 4, v:true))
-
-  " string with two byte characters
-  let str = "a©©b"
-  call assert_equal(0, byteidxcomp(str, 0, v:true))
-  call assert_equal(1, byteidxcomp(str, 1, v:true))
-  call assert_equal(3, byteidxcomp(str, 2, v:true))
-  call assert_equal(5, byteidxcomp(str, 3, v:true))
-  call assert_equal(6, byteidxcomp(str, 4, v:true))
-  call assert_equal(-1, byteidxcomp(str, 5, v:true))
-
-  " string with two byte characters
-  let str = "a😊😊b"
-  call assert_equal(0, byteidxcomp(str, 0, v:true))
-  call assert_equal(1, byteidxcomp(str, 1, v:true))
-  call assert_equal(1, byteidxcomp(str, 2, v:true))
-  call assert_equal(5, byteidxcomp(str, 3, v:true))
-  call assert_equal(5, byteidxcomp(str, 4, v:true))
-  call assert_equal(9, byteidxcomp(str, 5, v:true))
-  call assert_equal(10, byteidxcomp(str, 6, v:true))
-  call assert_equal(-1, byteidxcomp(str, 7, v:true))
-
-  " string with composing characters
-  let str = '-á-b́'
-  call assert_equal(0, byteidxcomp(str, 0, v:true))
-  call assert_equal(1, byteidxcomp(str, 1, v:true))
-  call assert_equal(2, byteidxcomp(str, 2, v:true))
-  call assert_equal(4, byteidxcomp(str, 3, v:true))
-  call assert_equal(5, byteidxcomp(str, 4, v:true))
-  call assert_equal(6, byteidxcomp(str, 5, v:true))
-  call assert_equal(8, byteidxcomp(str, 6, v:true))
-  call assert_equal(-1, byteidxcomp(str, 7, v:true))
-  call assert_fails('call byteidxcomp(str, 0, [])', 'E745:')
-
-  " string with multiple composing characters
-  let str = '-ą́-ą́'
-  call assert_equal(0, byteidxcomp(str, 0, v:true))
-  call assert_equal(1, byteidxcomp(str, 1, v:true))
-  call assert_equal(2, byteidxcomp(str, 2, v:true))
-  call assert_equal(4, byteidxcomp(str, 3, v:true))
-  call assert_equal(6, byteidxcomp(str, 4, v:true))
-  call assert_equal(7, byteidxcomp(str, 5, v:true))
-  call assert_equal(8, byteidxcomp(str, 6, v:true))
-  call assert_equal(10, byteidxcomp(str, 7, v:true))
-  call assert_equal(12, byteidxcomp(str, 8, v:true))
-  call assert_equal(-1, byteidxcomp(str, 9, v:true))
-
-  " empty string
-  call assert_equal(0, byteidxcomp('', 0, v:true))
-  call assert_equal(-1, byteidxcomp('', 1, v:true))
-
-  " error cases
-  call assert_fails('call byteidxcomp(str, 0, [])', 'E745:')
-endfunc
-
-" Test for charidx() using a byte index
-func Test_charidx()
-  let a = 'xáb́y'
-  call assert_equal(0, charidx(a, 0))
-  call assert_equal(1, charidx(a, 3))
-  call assert_equal(2, charidx(a, 4))
-  call assert_equal(3, charidx(a, 7))
-  call assert_equal(4, charidx(a, 8))
-  call assert_equal(-1, charidx(a, 9))
-  call assert_equal(-1, charidx(a, -1))
-
-  " count composing characters
-  call assert_equal(0, a->charidx(0, 1))
-  call assert_equal(2, a->charidx(2, 1))
-  call assert_equal(3, a->charidx(4, 1))
-  call assert_equal(5, a->charidx(7, 1))
-  call assert_equal(6, a->charidx(8, 1))
-  call assert_equal(-1, a->charidx(9, 1))
-
-  " empty string
-  call assert_equal(0, charidx('', 0))
-  call assert_equal(-1, charidx('', 1))
-  call assert_equal(0, charidx('', 0, 1))
-  call assert_equal(-1, charidx('', 1, 1))
-
-  " error cases
-  call assert_equal(0, charidx(test_null_string(), 0))
-  call assert_equal(-1, charidx(test_null_string(), 1))
-  call assert_fails('let x = charidx([], 1)', 'E1174:')
-  call assert_fails('let x = charidx("abc", [])', 'E1210:')
-  call assert_fails('let x = charidx("abc", 1, [])', 'E1212:')
-  call assert_fails('let x = charidx("abc", 1, -1)', 'E1212:')
-  call assert_fails('let x = charidx("abc", 1, 2)', 'E1212:')
-endfunc
-
-" Test for charidx() using a UTF-16 index
-func Test_charidx_from_utf16_index()
-  " string with single byte characters
-  let str = "abc"
-  for i in range(4)
-    call assert_equal(i, charidx(str, i, v:false, v:true))
-  endfor
-  call assert_equal(-1, charidx(str, 4, v:false, v:true))
-
-  " string with two byte characters
-  let str = "a©©b"
-  call assert_equal(0, charidx(str, 0, v:false, v:true))
-  call assert_equal(1, charidx(str, 1, v:false, v:true))
-  call assert_equal(2, charidx(str, 2, v:false, v:true))
-  call assert_equal(3, charidx(str, 3, v:false, v:true))
-  call assert_equal(4, charidx(str, 4, v:false, v:true))
-  call assert_equal(-1, charidx(str, 5, v:false, v:true))
-
-  " string with four byte characters
-  let str = "a😊😊b"
-  call assert_equal(0, charidx(str, 0, v:false, v:true))
-  call assert_equal(1, charidx(str, 1, v:false, v:true))
-  call assert_equal(1, charidx(str, 2, v:false, v:true))
-  call assert_equal(2, charidx(str, 3, v:false, v:true))
-  call assert_equal(2, charidx(str, 4, v:false, v:true))
-  call assert_equal(3, charidx(str, 5, v:false, v:true))
-  call assert_equal(4, charidx(str, 6, v:false, v:true))
-  call assert_equal(-1, charidx(str, 7, v:false, v:true))
-
-  " string with composing characters
-  let str = '-á-b́'
-  for i in str->strcharlen()->range()
-    call assert_equal(i, charidx(str, i, v:false, v:true))
-  endfor
-  call assert_equal(4, charidx(str, 4, v:false, v:true))
-  call assert_equal(-1, charidx(str, 5, v:false, v:true))
-  for i in str->strchars()->range()
-    call assert_equal(i, charidx(str, i, v:true, v:true))
-  endfor
-  call assert_equal(6, charidx(str, 6, v:true, v:true))
-  call assert_equal(-1, charidx(str, 7, v:true, v:true))
-
-  " string with multiple composing characters
-  let str = '-ą́-ą́'
-  for i in str->strcharlen()->range()
-    call assert_equal(i, charidx(str, i, v:false, v:true))
-  endfor
-  call assert_equal(4, charidx(str, 4, v:false, v:true))
-  call assert_equal(-1, charidx(str, 5, v:false, v:true))
-  for i in str->strchars()->range()
-    call assert_equal(i, charidx(str, i, v:true, v:true))
-  endfor
-  call assert_equal(8, charidx(str, 8, v:true, v:true))
-  call assert_equal(-1, charidx(str, 9, v:true, v:true))
-
-  " empty string
-  call assert_equal(0, charidx('', 0, v:false, v:true))
-  call assert_equal(-1, charidx('', 1, v:false, v:true))
-  call assert_equal(0, charidx('', 0, v:true, v:true))
-  call assert_equal(-1, charidx('', 1, v:true, v:true))
-
-  " error cases
-  call assert_equal(0, charidx('', 0, v:false, v:true))
-  call assert_equal(-1, charidx('', 1, v:false, v:true))
-  call assert_equal(0, charidx('', 0, v:true, v:true))
-  call assert_equal(-1, charidx('', 1, v:true, v:true))
-  call assert_equal(0, charidx(test_null_string(), 0, v:false, v:true))
-  call assert_equal(-1, charidx(test_null_string(), 1, v:false, v:true))
-  call assert_fails('let x = charidx("abc", 1, v:false, [])', 'E1212:')
-  call assert_fails('let x = charidx("abc", 1, v:true, [])', 'E1212:')
-endfunc
-
-" Test for utf16idx() using a byte index
-func Test_utf16idx_from_byteidx()
-  " UTF-16 index of a string with single byte characters
-  let str = "abc"
-  for i in range(4)
-    call assert_equal(i, utf16idx(str, i))
-  endfor
-  call assert_equal(-1, utf16idx(str, 4))
-
-  " UTF-16 index of a string with two byte characters
-  let str = 'a©©b'
-  call assert_equal(0, str->utf16idx(0))
-  call assert_equal(1, str->utf16idx(1))
-  call assert_equal(1, str->utf16idx(2))
-  call assert_equal(2, str->utf16idx(3))
-  call assert_equal(2, str->utf16idx(4))
-  call assert_equal(3, str->utf16idx(5))
-  call assert_equal(4, str->utf16idx(6))
-  call assert_equal(-1, str->utf16idx(7))
-
-  " UTF-16 index of a string with four byte characters
-  let str = 'a😊😊b'
-  call assert_equal(0, utf16idx(str, 0))
-  call assert_equal(1, utf16idx(str, 1))
-  call assert_equal(1, utf16idx(str, 2))
-  call assert_equal(1, utf16idx(str, 3))
-  call assert_equal(1, utf16idx(str, 4))
-  call assert_equal(3, utf16idx(str, 5))
-  call assert_equal(3, utf16idx(str, 6))
-  call assert_equal(3, utf16idx(str, 7))
-  call assert_equal(3, utf16idx(str, 8))
-  call assert_equal(5, utf16idx(str, 9))
-  call assert_equal(6, utf16idx(str, 10))
-  call assert_equal(-1, utf16idx(str, 11))
-
-  " UTF-16 index of a string with composing characters
-  let str = '-á-b́'
-  call assert_equal(0, utf16idx(str, 0))
-  call assert_equal(1, utf16idx(str, 1))
-  call assert_equal(1, utf16idx(str, 2))
-  call assert_equal(1, utf16idx(str, 3))
-  call assert_equal(2, utf16idx(str, 4))
-  call assert_equal(3, utf16idx(str, 5))
-  call assert_equal(3, utf16idx(str, 6))
-  call assert_equal(3, utf16idx(str, 7))
-  call assert_equal(4, utf16idx(str, 8))
-  call assert_equal(-1, utf16idx(str, 9))
-  call assert_equal(0, utf16idx(str, 0, v:true))
-  call assert_equal(1, utf16idx(str, 1, v:true))
-  call assert_equal(2, utf16idx(str, 2, v:true))
-  call assert_equal(2, utf16idx(str, 3, v:true))
-  call assert_equal(3, utf16idx(str, 4, v:true))
-  call assert_equal(4, utf16idx(str, 5, v:true))
-  call assert_equal(5, utf16idx(str, 6, v:true))
-  call assert_equal(5, utf16idx(str, 7, v:true))
-  call assert_equal(6, utf16idx(str, 8, v:true))
-  call assert_equal(-1, utf16idx(str, 9, v:true))
-
-  " string with multiple composing characters
-  let str = '-ą́-ą́'
-  call assert_equal(0, utf16idx(str, 0))
-  call assert_equal(1, utf16idx(str, 1))
-  call assert_equal(1, utf16idx(str, 2))
-  call assert_equal(1, utf16idx(str, 3))
-  call assert_equal(1, utf16idx(str, 4))
-  call assert_equal(1, utf16idx(str, 5))
-  call assert_equal(2, utf16idx(str, 6))
-  call assert_equal(3, utf16idx(str, 7))
-  call assert_equal(3, utf16idx(str, 8))
-  call assert_equal(3, utf16idx(str, 9))
-  call assert_equal(3, utf16idx(str, 10))
-  call assert_equal(3, utf16idx(str, 11))
-  call assert_equal(4, utf16idx(str, 12))
-  call assert_equal(-1, utf16idx(str, 13))
-  call assert_equal(0, utf16idx(str, 0, v:true))
-  call assert_equal(1, utf16idx(str, 1, v:true))
-  call assert_equal(2, utf16idx(str, 2, v:true))
-  call assert_equal(2, utf16idx(str, 3, v:true))
-  call assert_equal(3, utf16idx(str, 4, v:true))
-  call assert_equal(3, utf16idx(str, 5, v:true))
-  call assert_equal(4, utf16idx(str, 6, v:true))
-  call assert_equal(5, utf16idx(str, 7, v:true))
-  call assert_equal(6, utf16idx(str, 8, v:true))
-  call assert_equal(6, utf16idx(str, 9, v:true))
-  call assert_equal(7, utf16idx(str, 10, v:true))
-  call assert_equal(7, utf16idx(str, 11, v:true))
-  call assert_equal(8, utf16idx(str, 12, v:true))
-  call assert_equal(-1, utf16idx(str, 13, v:true))
-
-  " empty string
-  call assert_equal(0, utf16idx('', 0))
-  call assert_equal(-1, utf16idx('', 1))
-  call assert_equal(0, utf16idx('', 0, v:true))
-  call assert_equal(-1, utf16idx('', 1, v:true))
-
-  " error cases
-  call assert_equal(0, utf16idx("", 0))
-  call assert_equal(-1, utf16idx("", 1))
-  call assert_equal(-1, utf16idx("abc", -1))
-  call assert_equal(0, utf16idx(test_null_string(), 0))
-  call assert_equal(-1, utf16idx(test_null_string(), 1))
-  call assert_fails('let l = utf16idx([], 0)', 'E1174:')
-  call assert_fails('let l = utf16idx("ab", [])', 'E1210:')
-  call assert_fails('let l = utf16idx("ab", 0, [])', 'E1212:')
-endfunc
-
-" Test for utf16idx() using a character index
-func Test_utf16idx_from_charidx()
-  let str = "abc"
-  for i in str->strcharlen()->range()
-    call assert_equal(i, utf16idx(str, i, v:false, v:true))
-  endfor
-  call assert_equal(3, utf16idx(str, 3, v:false, v:true))
-  call assert_equal(-1, utf16idx(str, 4, v:false, v:true))
-
-  " UTF-16 index of a string with two byte characters
-  let str = "a©©b"
-  for i in str->strcharlen()->range()
-    call assert_equal(i, utf16idx(str, i, v:false, v:true))
-  endfor
-  call assert_equal(4, utf16idx(str, 4, v:false, v:true))
-  call assert_equal(-1, utf16idx(str, 5, v:false, v:true))
-
-  " UTF-16 index of a string with four byte characters
-  let str = "a😊😊b"
-  call assert_equal(0, utf16idx(str, 0, v:false, v:true))
-  call assert_equal(1, utf16idx(str, 1, v:false, v:true))
-  call assert_equal(3, utf16idx(str, 2, v:false, v:true))
-  call assert_equal(5, utf16idx(str, 3, v:false, v:true))
-  call assert_equal(6, utf16idx(str, 4, v:false, v:true))
-  call assert_equal(-1, utf16idx(str, 5, v:false, v:true))
-
-  " UTF-16 index of a string with composing characters
-  let str = '-á-b́'
-  for i in str->strcharlen()->range()
-    call assert_equal(i, utf16idx(str, i, v:false, v:true))
-  endfor
-  call assert_equal(4, utf16idx(str, 4, v:false, v:true))
-  call assert_equal(-1, utf16idx(str, 5, v:false, v:true))
-  for i in str->strchars()->range()
-    call assert_equal(i, utf16idx(str, i, v:true, v:true))
-  endfor
-  call assert_equal(6, utf16idx(str, 6, v:true, v:true))
-  call assert_equal(-1, utf16idx(str, 7, v:true, v:true))
-
-  " string with multiple composing characters
-  let str = '-ą́-ą́'
-  for i in str->strcharlen()->range()
-    call assert_equal(i, utf16idx(str, i, v:false, v:true))
-  endfor
-  call assert_equal(4, utf16idx(str, 4, v:false, v:true))
-  call assert_equal(-1, utf16idx(str, 5, v:false, v:true))
-  for i in str->strchars()->range()
-    call assert_equal(i, utf16idx(str, i, v:true, v:true))
-  endfor
-  call assert_equal(8, utf16idx(str, 8, v:true, v:true))
-  call assert_equal(-1, utf16idx(str, 9, v:true, v:true))
-
-  " empty string
-  call assert_equal(0, utf16idx('', 0, v:false, v:true))
-  call assert_equal(-1, utf16idx('', 1, v:false, v:true))
-  call assert_equal(0, utf16idx('', 0, v:true, v:true))
-  call assert_equal(-1, utf16idx('', 1, v:true, v:true))
-
-  " error cases
-  call assert_equal(0, utf16idx(test_null_string(), 0, v:true, v:true))
-  call assert_equal(-1, utf16idx(test_null_string(), 1, v:true, v:true))
-  call assert_fails('let l = utf16idx("ab", 0, v:false, [])', 'E1212:')
-endfunc
-
-" Test for strutf16len()
-func Test_strutf16len()
-  call assert_equal(3, strutf16len('abc'))
-  call assert_equal(3, 'abc'->strutf16len(v:true))
-  call assert_equal(4, strutf16len('a©©b'))
-  call assert_equal(4, strutf16len('a©©b', v:true))
-  call assert_equal(6, strutf16len('a😊😊b'))
-  call assert_equal(6, strutf16len('a😊😊b', v:true))
-  call assert_equal(4, strutf16len('-á-b́'))
-  call assert_equal(6, strutf16len('-á-b́', v:true))
-  call assert_equal(4, strutf16len('-ą́-ą́'))
-  call assert_equal(8, strutf16len('-ą́-ą́', v:true))
-  call assert_equal(0, strutf16len(''))
-
-  " error cases
-  call assert_fails('let l = strutf16len([])', 'E1174:')
-  call assert_fails('let l = strutf16len("a", [])', 'E1212:')
-  call assert_equal(0, strutf16len(test_null_string()))
-endfunc
-
-func Test_count()
-  let l = ['a', 'a', 'A', 'b']
-  call assert_equal(2, count(l, 'a'))
-  call assert_equal(1, count(l, 'A'))
-  call assert_equal(1, count(l, 'b'))
-  call assert_equal(0, count(l, 'B'))
-
-  call assert_equal(2, count(l, 'a', 0))
-  call assert_equal(1, count(l, 'A', 0))
-  call assert_equal(1, count(l, 'b', 0))
-  call assert_equal(0, count(l, 'B', 0))
-
-  call assert_equal(3, count(l, 'a', 1))
-  call assert_equal(3, count(l, 'A', 1))
-  call assert_equal(1, count(l, 'b', 1))
-  call assert_equal(1, count(l, 'B', 1))
-  call assert_equal(0, count(l, 'c', 1))
-
-  call assert_equal(1, count(l, 'a', 0, 1))
-  call assert_equal(2, count(l, 'a', 1, 1))
-  call assert_fails('call count(l, "a", 0, 10)', 'E684:')
-  call assert_fails('call count(l, "a", [])', 'E745:')
-
-  let d = {1: 'a', 2: 'a', 3: 'A', 4: 'b'}
-  call assert_equal(2, count(d, 'a'))
-  call assert_equal(1, count(d, 'A'))
-  call assert_equal(1, count(d, 'b'))
-  call assert_equal(0, count(d, 'B'))
-
-  call assert_equal(2, count(d, 'a', 0))
-  call assert_equal(1, count(d, 'A', 0))
-  call assert_equal(1, count(d, 'b', 0))
-  call assert_equal(0, count(d, 'B', 0))
-
-  call assert_equal(3, count(d, 'a', 1))
-  call assert_equal(3, count(d, 'A', 1))
-  call assert_equal(1, count(d, 'b', 1))
-  call assert_equal(1, count(d, 'B', 1))
-  call assert_equal(0, count(d, 'c', 1))
-
-  call assert_fails('call count(d, "a", 0, 1)', 'E474:')
-
-  call assert_equal(0, count("foo", "bar"))
-  call assert_equal(1, count("foo", "oo"))
-  call assert_equal(2, count("foo", "o"))
-  call assert_equal(0, count("foo", "O"))
-  call assert_equal(2, count("foo", "O", 1))
-  call assert_equal(2, count("fooooo", "oo"))
-  call assert_equal(0, count("foo", ""))
-
-  call assert_fails('call count(0, 0)', 'E712:')
-endfunc
-
-func Test_changenr()
-  new Xchangenr
-  call assert_equal(0, changenr())
-  norm ifoo
-  call assert_equal(1, changenr())
-  set undolevels=10
-  norm Sbar
-  call assert_equal(2, changenr())
-  undo
-  call assert_equal(1, changenr())
-  redo
-  call assert_equal(2, changenr())
-  bw!
-  set undolevels&
-endfunc
-
-func Test_filewritable()
-  new Xfilewritable
-  write!
-  call assert_equal(1, filewritable('Xfilewritable'))
-
-  call assert_notequal(0, setfperm('Xfilewritable', 'r--r-----'))
-  call assert_equal(0, filewritable('Xfilewritable'))
-
-  call assert_notequal(0, setfperm('Xfilewritable', 'rw-r-----'))
-  call assert_equal(1, 'Xfilewritable'->filewritable())
-
-  call assert_equal(0, filewritable('doesnotexist'))
-
-  call mkdir('Xwritedir', 'D')
-  call assert_equal(2, filewritable('Xwritedir'))
-
-  call delete('Xfilewritable')
-  bw!
-endfunc
-
-func Test_Executable()
-  if has('win32')
-    call assert_equal(1, executable('notepad'))
-    call assert_equal(1, 'notepad.exe'->executable())
-    call assert_equal(0, executable('notepad.exe.exe'))
-    call assert_equal(0, executable('shell32.dll'))
-    call assert_equal(0, executable('win.ini'))
-
-    " get "notepad" path and remove the leading drive and sep. (ex. 'C:\')
-    let notepadcmd = exepath('notepad.exe')
-    let driveroot = notepadcmd[:2]
-    let notepadcmd = notepadcmd[3:]
-    new
-    " check that the relative path works in /
-    execute 'lcd' driveroot
-    call assert_equal(1, executable(notepadcmd))
-    call assert_equal(driveroot .. notepadcmd, notepadcmd->exepath())
-    bwipe
-
-    " create "notepad.bat"
-    call mkdir('Xnotedir')
-    let notepadbat = fnamemodify('Xnotedir/notepad.bat', ':p')
-    call writefile([], notepadbat)
-    new
-    " check that the path and the pathext order is valid
-    lcd Xnotedir
-    let [pathext, $PATHEXT] = [$PATHEXT, '.com;.exe;.bat;.cmd']
-    call assert_equal(notepadbat, exepath('notepad'))
-    let $PATHEXT = pathext
-    bwipe
-    eval 'Xnotedir'->delete('rf')
-  elseif has('unix')
-    call assert_equal(1, 'cat'->executable())
-    call assert_equal(0, executable('nodogshere'))
-
-    " get "cat" path and remove the leading /
-    let catcmd = exepath('cat')[1:]
-    new
-    " check that the relative path works in /
-    lcd /
-    call assert_equal(1, executable(catcmd))
-    let result = catcmd->exepath()
-    " when using chroot looking for sbin/cat can return bin/cat, that is OK
-    if catcmd =~ '\<sbin\>' && result =~ '\<bin\>'
-      call assert_equal('/' .. substitute(catcmd, '\<sbin\>', 'bin', ''), result)
-    else
-      " /bin/cat and /usr/bin/cat may be hard linked, we could get either
-      let result = substitute(result, '/usr/bin/cat', '/bin/cat', '')
-      let catcmd = substitute(catcmd, 'usr/bin/cat', 'bin/cat', '')
-      call assert_equal('/' .. catcmd, result)
-    endif
-    bwipe
-  else
-    throw 'Skipped: does not work on this platform'
-  endif
-endfunc
-
-func Test_executable_windows_store_apps()
-  CheckMSWindows
-
-  " Windows Store apps install some 'decoy' .exe that require some careful
-  " handling as they behave similarly to symlinks.
-  let app_dir = expand("$LOCALAPPDATA\\Microsoft\\WindowsApps")
-  if !isdirectory(app_dir)
-    return
-  endif
-
-  let save_path = $PATH
-  let $PATH = app_dir
-  " Ensure executable() finds all the app .exes
-  for entry in readdir(app_dir)
-    if entry =~ '\.exe$'
-      call assert_true(executable(entry))
-    endif
-  endfor
-
-  let $PATH = save_path
-endfunc
-
-func Test_executable_longname()
-  CheckMSWindows
-
-  " Create a temporary .bat file with 205 characters in the name.
-  " Maximum length of a filename (including the path) on MS-Windows is 259
-  " characters.
-  " See https://docs.microsoft.com/en-us/windows/win32/fileio/maximum-file-path-limitation
-  let len = 259 - getcwd()->len() - 6
-  if len > 200
-    let len = 200
-  endif
-
-  let fname = 'X' . repeat('あ', len) . '.bat'
-  call writefile([], fname)
-  call assert_equal(1, executable(fname))
-  call delete(fname)
-endfunc
-
-func Test_hostname()
-  let hostname_vim = hostname()
-  if has('unix')
-    let hostname_system = systemlist('uname -n')[0]
-    call assert_equal(hostname_vim, hostname_system)
-  endif
-endfunc
-
-func Test_getpid()
-  " getpid() always returns the same value within a vim instance.
-  call assert_equal(getpid(), getpid())
-  if has('unix')
-    call assert_equal(systemlist('echo $PPID')[0], string(getpid()))
-  endif
-endfunc
-
-func Test_hlexists()
-  call assert_equal(0, hlexists('does_not_exist'))
-  call assert_equal(0, 'Number'->hlexists())
-  call assert_equal(0, highlight_exists('does_not_exist'))
-  call assert_equal(0, highlight_exists('Number'))
-  syntax on
-  call assert_equal(0, hlexists('does_not_exist'))
-  call assert_equal(1, hlexists('Number'))
-  call assert_equal(0, highlight_exists('does_not_exist'))
-  call assert_equal(1, highlight_exists('Number'))
-  syntax off
-endfunc
-
-" Test for the col() function
-func Test_col()
-  new
-  call setline(1, 'abcdef')
-  norm gg4|mx6|mY2|
-  call assert_equal(2, col('.'))
-  call assert_equal(7, col('$'))
-  call assert_equal(2, col('v'))
-  call assert_equal(4, col("'x"))
-  call assert_equal(6, col("'Y"))
-  call assert_equal(2, [1, 2]->col())
-  call assert_equal(7, col([1, '$']))
-
-  call assert_equal(0, col(''))
-  call assert_equal(0, col('x'))
-  call assert_equal(0, col([2, '$']))
-  call assert_equal(0, col([1, 100]))
-  call assert_equal(0, col([1]))
-  call assert_equal(0, col(test_null_list()))
-  call assert_fails('let c = col({})', 'E1222:')
-  call assert_fails('let c = col(".", [])', 'E1210:')
-
-  " test for getting the visual start column
-  func T()
-    let g:Vcol = col('v')
-    return ''
-  endfunc
-  let g:Vcol = 0
-  xmap <expr> <F2> T()
-  exe "normal gg3|ve\<F2>"
-  call assert_equal(3, g:Vcol)
-  xunmap <F2>
-  delfunc T
-
-  " Test for the visual line start and end marks '< and '>
-  call setline(1, ['one', 'one two', 'one two three'])
-  "normal! ggVG
-  call feedkeys("ggVG\<Esc>", 'xt')
-  call assert_equal(1, col("'<"))
-  call assert_equal(14, col("'>"))
-  " Delete the last line of the visually selected region
-  $d
-  call assert_notequal(14, col("'>"))
-
-  " Test with 'virtualedit'
-  set virtualedit=all
-  call cursor(1, 10)
-  call assert_equal(4, col('.'))
-  set virtualedit&
-
-  " Test for getting the column number in another window
-  let winid = win_getid()
-  new
-  call win_execute(winid, 'normal 1G$')
-  call assert_equal(3, col('.', winid))
-  call win_execute(winid, 'normal 2G')
-  call assert_equal(8, col('$', winid))
-  call assert_equal(0, col('.', 5001))
-
-  bw!
-endfunc
-
-" Test for input()
-func Test_input_func()
-  " Test for prompt with multiple lines
-  redir => v
-  call feedkeys(":let c = input(\"A\\nB\\nC\\n? \")\<CR>B\<CR>", 'xt')
-  redir END
-  call assert_equal("B", c)
-  call assert_equal(['A', 'B', 'C'], split(v, "\n"))
-
-  " Test for default value
-  call feedkeys(":let c = input('color? ', 'red')\<CR>\<CR>", 'xt')
-  call assert_equal('red', c)
-
-  " Test for completion at the input prompt
-  func! Tcomplete(arglead, cmdline, pos)
-    return "item1\nitem2\nitem3"
-  endfunc
-  call feedkeys(":let c = input('Q? ', '', 'custom,Tcomplete')\<CR>"
-        \ .. "\<C-A>\<CR>", 'xt')
-  delfunc Tcomplete
-  call assert_equal('item1 item2 item3', c)
-
-  " Test for using special characters as default input
-  call feedkeys(":let c = input('name? ', \"x\\<BS>y\")\<CR>\<CR>", 'xt')
-  call assert_equal('y', c)
-
-  " Test for using text with composing characters as default input
-  call feedkeys(":let c = input('name? ', \"ã̳\")\<CR>\<CR>", 'xt')
-  call assert_equal('ã̳', c)
-
-  " Test for using <CR> as default input
-  call feedkeys(":let c = input('name? ', \"\\<CR>\")\<CR>x\<CR>", 'xt')
-  call assert_equal(' x', c)
-
-  call assert_fails("call input('F:', '', 'invalid')", 'E180:')
-  call assert_fails("call input('F:', '', [])", 'E730:')
-endfunc
-
-" Test for the inputdialog() function
-func Test_inputdialog()
-  set timeout timeoutlen=10
-  if has('gui_running')
-    call assert_fails('let v=inputdialog([], "xx")', 'E730:')
-    call assert_fails('let v=inputdialog("Q", [])', 'E730:')
-  else
-    call feedkeys(":let v=inputdialog('Q:', 'xx', 'yy')\<CR>\<CR>", 'xt')
-    call assert_equal('xx', v)
-    call feedkeys(":let v=inputdialog('Q:', 'xx', 'yy')\<CR>\<Esc>", 'xt')
-    call assert_equal('yy', v)
-  endif
-  set timeout& timeoutlen&
-endfunc
-
-" Test for inputlist()
-func Test_inputlist()
-  call feedkeys(":let c = inputlist(['Select color:', '1. red', '2. green', '3. blue'])\<cr>1\<cr>", 'tx')
-  call assert_equal(1, c)
-  call feedkeys(":let c = ['Select color:', '1. red', '2. green', '3. blue']->inputlist()\<cr>2\<cr>", 'tx')
-  call assert_equal(2, c)
-  call feedkeys(":let c = inputlist(['Select color:', '1. red', '2. green', '3. blue'])\<cr>3\<cr>", 'tx')
-  call assert_equal(3, c)
-
-  " CR to cancel
-  call feedkeys(":let c = inputlist(['Select color:', '1. red', '2. green', '3. blue'])\<cr>\<cr>", 'tx')
-  call assert_equal(0, c)
-
-  " Esc to cancel
-  call feedkeys(":let c = inputlist(['Select color:', '1. red', '2. green', '3. blue'])\<cr>\<Esc>", 'tx')
-  call assert_equal(0, c)
-
-  " q to cancel
-  call feedkeys(":let c = inputlist(['Select color:', '1. red', '2. green', '3. blue'])\<cr>q", 'tx')
-  call assert_equal(0, c)
-
-  " Cancel after inputting a number
-  call feedkeys(":let c = inputlist(['Select color:', '1. red', '2. green', '3. blue'])\<cr>5q", 'tx')
-  call assert_equal(0, c)
-
-  " Use backspace to delete characters in the prompt
-  call feedkeys(":let c = inputlist(['Select color:', '1. red', '2. green', '3. blue'])\<cr>1\<BS>3\<BS>2\<cr>", 'tx')
-  call assert_equal(2, c)
-
-  " Use mouse to make a selection
-  call test_setmouse(&lines - 3, 2)
-  call feedkeys(":let c = inputlist(['Select color:', '1. red', '2. green', '3. blue'])\<cr>\<LeftMouse>", 'tx')
-  call assert_equal(1, c)
-  " Mouse click outside of the list
-  call test_setmouse(&lines - 6, 2)
-  call feedkeys(":let c = inputlist(['Select color:', '1. red', '2. green', '3. blue'])\<cr>\<LeftMouse>", 'tx')
-  call assert_equal(-2, c)
-
-  call assert_fails('call inputlist("")', 'E686:')
-  call assert_fails('call inputlist(test_null_list())', 'E686:')
-endfunc
-
-func Test_range_inputlist()
-  " flush out any garbage left in the buffer
-  while getchar(0)
-  endwhile
-
-  call feedkeys(":let result = inputlist(range(10))\<CR>1\<CR>", 'x')
-  call assert_equal(1, result)
-  call feedkeys(":let result = inputlist(range(3, 10))\<CR>1\<CR>", 'x')
-  call assert_equal(1, result)
-
-  unlet result
-endfunc
-
-func Test_balloon_show()
-  CheckFeature balloon_eval
-
-  " This won't do anything but must not crash either.
-  call balloon_show('hi!')
-  if !has('gui_running')
-    call balloon_show(range(3))
-    call balloon_show([])
-  endif
-endfunc
-
-func Test_setbufvar_options()
-  " This tests that aucmd_prepbuf() and aucmd_restbuf() properly restore the
-  " window layout and cursor position.
-  call assert_equal(1, winnr('$'))
-  split dummy_preview
-  resize 2
-  set winfixheight winfixwidth
-  let prev_id = win_getid()
-
-  wincmd j
-  let wh = winheight(0)
-  let dummy_buf = bufnr('dummy_buf1', v:true)
-  call setbufvar(dummy_buf, '&buftype', 'nofile')
-  execute 'belowright vertical split #' . dummy_buf
-  call assert_equal(wh, winheight(0))
-  let dum1_id = win_getid()
-  call setline(1, 'foo')
-  normal! V$
-  call assert_equal(4, col('.'))
-  call setbufvar('dummy_preview', '&buftype', 'nofile')
-  call assert_equal(4, col('.'))
-
-  wincmd h
-  let wh = winheight(0)
-  call setline(1, 'foo')
-  normal! V$
-  call assert_equal(4, col('.'))
-  let dummy_buf = bufnr('dummy_buf2', v:true)
-  eval 'nofile'->setbufvar(dummy_buf, '&buftype')
-  call assert_equal(4, col('.'))
-  execute 'belowright vertical split #' . dummy_buf
-  call assert_equal(wh, winheight(0))
-
-  bwipe!
-  call win_gotoid(prev_id)
-  bwipe!
-  call win_gotoid(dum1_id)
-  bwipe!
-endfunc
-
-func Test_setbufvar_keep_window_title()
-  CheckRunVimInTerminal
-  if !has('title') || empty(&t_ts)
-    throw "Skipped: can't get/set title"
-  endif
-
-  let lines =<< trim END
-      set title
-      edit Xa.txt
-      let g:buf = bufadd('Xb.txt')
-      inoremap <F2> <C-R>=setbufvar(g:buf, '&autoindent', 1) ?? ''<CR>
-  END
-  call writefile(lines, 'Xsetbufvar', 'D')
-  let buf = RunVimInTerminal('-S Xsetbufvar', {})
-  call WaitForAssert({-> assert_match('Xa.txt', term_gettitle(buf))}, 1000)
-
-  call term_sendkeys(buf, "i\<F2>")
-  call TermWait(buf)
-  call term_sendkeys(buf, "\<Esc>")
-  call TermWait(buf)
-  call assert_match('Xa.txt', term_gettitle(buf))
-
-  call StopVimInTerminal(buf)
-endfunc
-
-func Test_redo_in_nested_functions()
-  nnoremap g. :set opfunc=Operator<CR>g@
-  function Operator( type, ... )
-     let @x = 'XXX'
-     execute 'normal! g`[' . (a:type ==# 'line' ? 'V' : 'v') . 'g`]' . '"xp'
-  endfunction
-
-  function! Apply()
-      5,6normal! .
-  endfunction
-
-  new
-  call setline(1, repeat(['some "quoted" text', 'more "quoted" text'], 3))
-  1normal g.i"
-  call assert_equal('some "XXX" text', getline(1))
-  3,4normal .
-  call assert_equal('some "XXX" text', getline(3))
-  call assert_equal('more "XXX" text', getline(4))
-  call Apply()
-  call assert_equal('some "XXX" text', getline(5))
-  call assert_equal('more "XXX" text', getline(6))
-  bwipe!
-
-  nunmap g.
-  delfunc Operator
-  delfunc Apply
-endfunc
-
-func Test_trim()
-  call assert_equal("Testing", trim("  \t\r\r\x0BTesting  \t\n\r\n\t\x0B\x0B"))
-  call assert_equal("Testing", "  \t  \r\r\n\n\x0BTesting  \t\n\r\n\t\x0B\x0B"->trim())
-  call assert_equal("RESERVE", trim("xyz \twwRESERVEzyww \t\t", " wxyz\t"))
-  call assert_equal("wRE    \tSERVEzyww", trim("wRE    \tSERVEzyww"))
-  call assert_equal("abcd\t     xxxx   tail", trim(" \tabcd\t     xxxx   tail"))
-  call assert_equal("\tabcd\t     xxxx   tail", trim(" \tabcd\t     xxxx   tail", " "))
-  call assert_equal(" \tabcd\t     xxxx   tail", trim(" \tabcd\t     xxxx   tail", "abx"))
-  call assert_equal("RESERVE", trim("你RESERVE好", "你好"))
-  call assert_equal("您R E SER V E早", trim("你好您R E SER V E早好你你", "你好"))
-  call assert_equal("你好您R E SER V E早好你你", trim(" \n\r\r   你好您R E SER V E早好你你    \t  \x0B", ))
-  call assert_equal("您R E SER V E早好你你    \t  \x0B", trim("    你好您R E SER V E早好你你    \t  \x0B", " 你好"))
-  call assert_equal("您R E SER V E早好你你    \t  \x0B", trim("    tteesstttt你好您R E SER V E早好你你    \t  \x0B ttestt", " 你好tes"))
-  call assert_equal("您R E SER V E早好你你    \t  \x0B", trim("    tteesstttt你好您R E SER V E早好你你    \t  \x0B ttestt", "   你你你好好好tttsses"))
-  call assert_equal("留下", trim("这些些不要这些留下这些", "这些不要"))
-  call assert_equal("", trim("", ""))
-  call assert_equal("a", trim("a", ""))
-  call assert_equal("", trim("", "a"))
-
-  call assert_equal("vim", trim("  vim  ", " ", 0))
-  call assert_equal("vim  ", trim("  vim  ", " ", 1))
-  call assert_equal("  vim", trim("  vim  ", " ", 2))
-  call assert_fails('eval trim("  vim  ", " ", [])', 'E745:')
-  call assert_fails('eval trim("  vim  ", " ", -1)', 'E475:')
-  call assert_fails('eval trim("  vim  ", " ", 3)', 'E475:')
-  call assert_fails('eval trim("  vim  ", 0)', 'E1174:')
-
-  let chars = join(map(range(1, 0x20) + [0xa0], {n -> n->nr2char()}), '')
-  call assert_equal("x", trim(chars . "x" . chars))
-
-  call assert_fails('let c=trim([])', 'E730:')
-endfunc
-
-" Test for reg_recording() and reg_executing()
-func Test_reg_executing_and_recording()
-  let s:reg_stat = ''
-  func s:save_reg_stat()
-    let s:reg_stat = reg_recording() . ':' . reg_executing()
-    return ''
-  endfunc
-
-  new
-  call s:save_reg_stat()
-  call assert_equal(':', s:reg_stat)
-  call feedkeys("qa\"=s:save_reg_stat()\<CR>pq", 'xt')
-  call assert_equal('a:', s:reg_stat)
-  call feedkeys("@a", 'xt')
-  call assert_equal(':a', s:reg_stat)
-  call feedkeys("qb@aq", 'xt')
-  call assert_equal('b:a', s:reg_stat)
-  call feedkeys("q\"\"=s:save_reg_stat()\<CR>pq", 'xt')
-  call assert_equal('":', s:reg_stat)
-
-  " :normal command saves and restores reg_executing
-  let s:reg_stat = ''
-  let @q = ":call TestFunc()\<CR>:call s:save_reg_stat()\<CR>"
-  func TestFunc() abort
-    normal! ia
-  endfunc
-  call feedkeys("@q", 'xt')
-  call assert_equal(':q', s:reg_stat)
-  delfunc TestFunc
-
-  " getchar() command saves and restores reg_executing
-  map W :call TestFunc()<CR>
-  let @q = "W"
-  let g:typed = ''
-  let g:regs = []
-  func TestFunc() abort
-    let g:regs += [reg_executing()]
-    let g:typed = getchar(0)
-    let g:regs += [reg_executing()]
-  endfunc
-  call feedkeys("@qy", 'xt')
-  call assert_equal(char2nr("y"), g:typed)
-  call assert_equal(['q', 'q'], g:regs)
-  delfunc TestFunc
-  unmap W
-  unlet g:typed
-  unlet g:regs
-
-  " input() command saves and restores reg_executing
-  map W :call TestFunc()<CR>
-  let @q = "W"
-  let g:typed = ''
-  let g:regs = []
-  func TestFunc() abort
-    let g:regs += [reg_executing()]
-    let g:typed = '?'->input()
-    let g:regs += [reg_executing()]
-  endfunc
-  call feedkeys("@qy\<CR>", 'xt')
-  call assert_equal("y", g:typed)
-  call assert_equal(['q', 'q'], g:regs)
-  delfunc TestFunc
-  unmap W
-  unlet g:typed
-  unlet g:regs
-
-  bwipe!
-  delfunc s:save_reg_stat
-  unlet s:reg_stat
-endfunc
-
-func Test_inputsecret()
-  map W :call TestFunc()<CR>
-  let @q = "W"
-  let g:typed1 = ''
-  let g:typed2 = ''
-  let g:regs = []
-  func TestFunc() abort
-    let g:typed1 = '?'->inputsecret()
-    let g:typed2 = inputsecret('password: ')
-  endfunc
-  call feedkeys("@qsomething\<CR>else\<CR>", 'xt')
-  call assert_equal("something", g:typed1)
-  call assert_equal("else", g:typed2)
-  delfunc TestFunc
-  unmap W
-  unlet g:typed1
-  unlet g:typed2
-endfunc
-
-func Test_getchar()
-  call feedkeys('a', '')
-  call assert_equal(char2nr('a'), getchar())
-  call assert_equal(0, getchar(0))
-  call assert_equal(0, getchar(1))
-
-  call feedkeys('a', '')
-  call assert_equal('a', getcharstr())
-  call assert_equal('', getcharstr(0))
-  call assert_equal('', getcharstr(1))
-
-  call feedkeys("\<M-F2>", '')
-  call assert_equal("\<M-F2>", getchar(0))
-  call assert_equal(0, getchar(0))
-
-  call setline(1, 'xxxx')
-  call test_setmouse(1, 3)
-  let v:mouse_win = 9
-  let v:mouse_winid = 9
-  let v:mouse_lnum = 9
-  let v:mouse_col = 9
-  call feedkeys("\<S-LeftMouse>", '')
-  call assert_equal("\<S-LeftMouse>", getchar())
-  call assert_equal(1, v:mouse_win)
-  call assert_equal(win_getid(1), v:mouse_winid)
-  call assert_equal(1, v:mouse_lnum)
-  call assert_equal(3, v:mouse_col)
-  enew!
-endfunc
-
-func Test_libcall_libcallnr()
-  CheckFeature libcall
-
-  if has('win32')
-    let libc = 'msvcrt.dll'
-  elseif has('mac')
-    let libc = 'libSystem.B.dylib'
-  elseif executable('ldd')
-    let libc = matchstr(split(system('ldd ' . GetVimProg())), '/libc\.so\>')
-  endif
-  if get(l:, 'libc', '') ==# ''
-    " On Unix, libc.so can be in various places.
-    if has('linux')
-      " There is not documented but regarding the 1st argument of glibc's
-      " dlopen an empty string and nullptr are equivalent, so using an empty
-      " string for the 1st argument of libcall allows to call functions.
-      let libc = ''
-    elseif has('sun')
-      " Set the path to libc.so according to the architecture.
-      let test_bits = system('file ' . GetVimProg())
-      let test_arch = system('uname -p')
-      if test_bits =~ '64-bit' && test_arch =~ 'sparc'
-        let libc = '/usr/lib/sparcv9/libc.so'
-      elseif test_bits =~ '64-bit' && test_arch =~ 'i386'
-        let libc = '/usr/lib/amd64/libc.so'
-      else
-        let libc = '/usr/lib/libc.so'
-      endif
-    else
-      " Unfortunately skip this test until a good way is found.
-      return
-    endif
-  endif
-
-  if has('win32')
-    call assert_equal($USERPROFILE, 'USERPROFILE'->libcall(libc, 'getenv'))
-  else
-    call assert_equal($HOME, 'HOME'->libcall(libc, 'getenv'))
-  endif
-
-  " If function returns NULL, libcall() should return an empty string.
-  call assert_equal('', libcall(libc, 'getenv', 'X_ENV_DOES_NOT_EXIT'))
-
-  " Test libcallnr() with string and integer argument.
-  call assert_equal(4, 'abcd'->libcallnr(libc, 'strlen'))
-  call assert_equal(char2nr('A'), char2nr('a')->libcallnr(libc, 'toupper'))
-
-  call assert_fails("call libcall(libc, 'Xdoesnotexist_', '')", ['', 'E364:'])
-  call assert_fails("call libcallnr(libc, 'Xdoesnotexist_', '')", ['', 'E364:'])
-
-  call assert_fails("call libcall('Xdoesnotexist_', 'getenv', 'HOME')", ['', 'E364:'])
-  call assert_fails("call libcallnr('Xdoesnotexist_', 'strlen', 'abcd')", ['', 'E364:'])
-endfunc
-
-sandbox function Fsandbox()
-  normal ix
-endfunc
-
-func Test_func_sandbox()
-  sandbox let F = {-> 'hello'}
-  call assert_equal('hello', F())
-
-  sandbox let F = {-> "normal ix\<Esc>"->execute()}
-  call assert_fails('call F()', 'E48:')
-  unlet F
-
-  call assert_fails('call Fsandbox()', 'E48:')
-  delfunc Fsandbox
-
-  " From a sandbox try to set a predefined variable (which cannot be modified
-  " from a sandbox)
-  call assert_fails('sandbox let v:lnum = 10', 'E794:')
-endfunc
-
-func EditAnotherFile()
-  let word = expand('<cword>')
-  edit Xfuncrange2
-endfunc
-
-func Test_func_range_with_edit()
-  " Define a function that edits another buffer, then call it with a range that
-  " is invalid in that buffer.
-  call writefile(['just one line'], 'Xfuncrange2', 'D')
-  new
-  eval 10->range()->setline(1)
-  write Xfuncrange1
-  call assert_fails('5,8call EditAnotherFile()', 'E16:')
-
-  call delete('Xfuncrange1')
-  bwipe!
-endfunc
-
-func Test_func_exists_on_reload()
-  call writefile(['func ExistingFunction()', 'echo "yes"', 'endfunc'], 'Xfuncexists', 'D')
-  call assert_equal(0, exists('*ExistingFunction'))
-  source Xfuncexists
-  call assert_equal(1, '*ExistingFunction'->exists())
-  " Redefining a function when reloading a script is OK.
-  source Xfuncexists
-  call assert_equal(1, exists('*ExistingFunction'))
-
-  " But redefining in another script is not OK.
-  call writefile(['func ExistingFunction()', 'echo "yes"', 'endfunc'], 'Xfuncexists2', 'D')
-  call assert_fails('source Xfuncexists2', 'E122:')
-
-  " Defining a new function from the cmdline should fail if the function is
-  " already defined
-  call assert_fails('call feedkeys(":func ExistingFunction()\<CR>", "xt")', 'E122:')
-
-  delfunc ExistingFunction
-  call assert_equal(0, exists('*ExistingFunction'))
-  call writefile([
-	\ 'func ExistingFunction()', 'echo "yes"', 'endfunc',
-	\ 'func ExistingFunction()', 'echo "no"', 'endfunc',
-	\ ], 'Xfuncexists')
-  call assert_fails('source Xfuncexists', 'E122:')
-  call assert_equal(1, exists('*ExistingFunction'))
-
-  delfunc ExistingFunction
-endfunc
-
-" Test confirm({msg} [, {choices} [, {default} [, {type}]]])
-func Test_confirm()
-  CheckUnix
-  CheckNotGui
-
-  call feedkeys('o', 'L')
-  let a = confirm('Press O to proceed')
-  call assert_equal(1, a)
-
-  call feedkeys('y', 'L')
-  let a = 'Are you sure?'->confirm("&Yes\n&No")
-  call assert_equal(1, a)
-
-  call feedkeys('n', 'L')
-  let a = confirm('Are you sure?', "&Yes\n&No")
-  call assert_equal(2, a)
-
-  " confirm() should return 0 when pressing CTRL-C.
-  call feedkeys("\<C-C>", 'L')
-  let a = confirm('Are you sure?', "&Yes\n&No")
-  call assert_equal(0, a)
-
-  " <Esc> requires another character to avoid it being seen as the start of an
-  " escape sequence.  Zero should be harmless.
-  eval "\<Esc>0"->feedkeys('L')
-  let a = confirm('Are you sure?', "&Yes\n&No")
-  call assert_equal(0, a)
-
-  " Default choice is returned when pressing <CR>.
-  call feedkeys("\<CR>", 'L')
-  let a = confirm('Are you sure?', "&Yes\n&No")
-  call assert_equal(1, a)
-
-  call feedkeys("\<CR>", 'L')
-  let a = confirm('Are you sure?', "&Yes\n&No", 2)
-  call assert_equal(2, a)
-
-  call feedkeys("\<CR>", 'L')
-  let a = confirm('Are you sure?', "&Yes\n&No", 0)
-  call assert_equal(0, a)
-
-  " Test with the {type} 4th argument
-  for type in ['Error', 'Question', 'Info', 'Warning', 'Generic']
-    call feedkeys('y', 'L')
-    let a = confirm('Are you sure?', "&Yes\n&No\n", 1, type)
-    call assert_equal(1, a)
-  endfor
-
-  call assert_fails('call confirm([])', 'E730:')
-  call assert_fails('call confirm("Are you sure?", [])', 'E730:')
-  call assert_fails('call confirm("Are you sure?", "&Yes\n&No\n", [])', 'E745:')
-  call assert_fails('call confirm("Are you sure?", "&Yes\n&No\n", 0, [])', 'E730:')
-endfunc
-
-func Test_platform_name()
-  " The system matches at most only one name.
-  let names = ['amiga', 'bsd', 'hpux', 'linux', 'mac', 'qnx', 'sun', 'vms', 'win32', 'win32unix']
-  call assert_inrange(0, 1, len(filter(copy(names), 'has(v:val)')))
-
-  " Is Unix?
-  call assert_equal(has('bsd'), has('bsd') && has('unix'))
-  call assert_equal(has('hpux'), has('hpux') && has('unix'))
-  call assert_equal(has('linux'), has('linux') && has('unix'))
-  call assert_equal(has('mac'), has('mac') && has('unix'))
-  call assert_equal(has('qnx'), has('qnx') && has('unix'))
-  call assert_equal(has('sun'), has('sun') && has('unix'))
-  call assert_equal(has('win32'), has('win32') && !has('unix'))
-  call assert_equal(has('win32unix'), has('win32unix') && has('unix'))
-
-  if has('unix') && executable('uname')
-    let uname = system('uname')
-    " GNU userland on BSD kernels (e.g., GNU/kFreeBSD) don't have BSD defined
-    call assert_equal(uname =~? '\%(GNU/k\w\+\)\@<!BSD\|DragonFly', has('bsd'))
-    call assert_equal(uname =~? 'HP-UX', has('hpux'))
-    call assert_equal(uname =~? 'Linux', has('linux'))
-    call assert_equal(uname =~? 'Darwin', has('mac'))
-    call assert_equal(uname =~? 'QNX', has('qnx'))
-    call assert_equal(uname =~? 'SunOS', has('sun'))
-    call assert_equal(uname =~? 'CYGWIN\|MSYS', has('win32unix'))
-  endif
-endfunc
-
-func Test_readdir()
-  call mkdir('Xreaddir', 'R')
-  call writefile([], 'Xreaddir/foo.txt')
-  call writefile([], 'Xreaddir/bar.txt')
-  call mkdir('Xreaddir/dir')
-
-  " All results
-  let files = readdir('Xreaddir')
-  call assert_equal(['bar.txt', 'dir', 'foo.txt'], sort(files))
-
-  " Only results containing "f"
-  let files = 'Xreaddir'->readdir({ x -> stridx(x, 'f') != -1 })
-  call assert_equal(['foo.txt'], sort(files))
-
-  " Only .txt files
-  let files = readdir('Xreaddir', { x -> x =~ '.txt$' })
-  call assert_equal(['bar.txt', 'foo.txt'], sort(files))
-
-  " Only .txt files with string
-  let files = readdir('Xreaddir', 'v:val =~ ".txt$"')
-  call assert_equal(['bar.txt', 'foo.txt'], sort(files))
-
-  " Limit to 1 result.
-  let l = []
-  let files = readdir('Xreaddir', {x -> len(add(l, x)) == 2 ? -1 : 1})
-  call assert_equal(1, len(files))
-
-  " Nested readdir() must not crash
-  let files = readdir('Xreaddir', 'readdir("Xreaddir", "1") != []')
-  call sort(files)->assert_equal(['bar.txt', 'dir', 'foo.txt'])
-endfunc
-
-func Test_readdirex()
-  call mkdir('Xexdir', 'R')
-  call writefile(['foo'], 'Xexdir/foo.txt')
-  call writefile(['barbar'], 'Xexdir/bar.txt')
-  call mkdir('Xexdir/dir')
-
-  " All results
-  let files = readdirex('Xexdir')->map({-> v:val.name})
-  call assert_equal(['bar.txt', 'dir', 'foo.txt'], sort(files))
-  let sizes = readdirex('Xexdir')->map({-> v:val.size})
-  call assert_equal([0, 4, 7], sort(sizes))
-
-  " Only results containing "f"
-  let files = 'Xexdir'->readdirex({ e -> stridx(e.name, 'f') != -1 })
-			  \ ->map({-> v:val.name})
-  call assert_equal(['foo.txt'], sort(files))
-
-  " Only .txt files
-  let files = readdirex('Xexdir', { e -> e.name =~ '.txt$' })
-			  \ ->map({-> v:val.name})
-  call assert_equal(['bar.txt', 'foo.txt'], sort(files))
-
-  " Only .txt files with string
-  let files = readdirex('Xexdir', 'v:val.name =~ ".txt$"')
-			  \ ->map({-> v:val.name})
-  call assert_equal(['bar.txt', 'foo.txt'], sort(files))
-
-  " Limit to 1 result.
-  let l = []
-  let files = readdirex('Xexdir', {e -> len(add(l, e.name)) == 2 ? -1 : 1})
-			  \ ->map({-> v:val.name})
-  call assert_equal(1, len(files))
-
-  " Nested readdirex() must not crash
-  let files = readdirex('Xexdir', 'readdirex("Xexdir", "1") != []')
-			  \ ->map({-> v:val.name})
-  call sort(files)->assert_equal(['bar.txt', 'dir', 'foo.txt'])
-
-  " report broken link correctly
-  if has("unix")
-    call writefile([], 'Xexdir/abc.txt')
-    call system("ln -s Xexdir/abc.txt Xexdir/link")
-    call delete('Xexdir/abc.txt')
-    let files = readdirex('Xexdir', 'readdirex("Xexdir", "1") != []')
-			  \ ->map({-> v:val.name .. '_' .. v:val.type})
-    call sort(files)->assert_equal(
-        \ ['bar.txt_file', 'dir_dir', 'foo.txt_file', 'link_link'])
-  endif
-
-  call assert_fails('call readdirex("doesnotexist")', 'E484:')
-endfunc
-
-func Test_readdirex_sort()
-  CheckUnix
-  " Skip tests on Mac OS X and Cygwin (does not allow several files with different casing)
-  if has("osxdarwin") || has("osx") || has("macunix") || has("win32unix")
-    throw 'Skipped: Test_readdirex_sort on systems that do not allow this using the default filesystem'
-  endif
-  let _collate = v:collate
-  call mkdir('Xsortdir2', 'R')
-  call writefile(['1'], 'Xsortdir2/README.txt')
-  call writefile(['2'], 'Xsortdir2/Readme.txt')
-  call writefile(['3'], 'Xsortdir2/readme.txt')
-
-  " 1) default
-  let files = readdirex('Xsortdir2')->map({-> v:val.name})
-  let default = copy(files)
-  call assert_equal(['README.txt', 'Readme.txt', 'readme.txt'], files, 'sort using default')
-
-  " 2) no sorting
-  let files = readdirex('Xsortdir2', 1, #{sort: 'none'})->map({-> v:val.name})
-  let unsorted = copy(files)
-  call assert_equal(['README.txt', 'Readme.txt', 'readme.txt'], sort(files), 'unsorted')
-  call assert_fails("call readdirex('Xsortdir2', 1, #{slort: 'none'})", 'E857: Dictionary key "sort" required')
-
-  " 3) sort by case (same as default)
-  let files = readdirex('Xsortdir2', 1, #{sort: 'case'})->map({-> v:val.name})
-  call assert_equal(default, files, 'sort by case')
-
-  " 4) sort by ignoring case
-  let files = readdirex('Xsortdir2', 1, #{sort: 'icase'})->map({-> v:val.name})
-  call assert_equal(unsorted->sort('i'), files, 'sort by icase')
-
-  " 5) Default Collation
-  let collate = v:collate
-  lang collate C
-  let files = readdirex('Xsortdir2', 1, #{sort: 'collate'})->map({-> v:val.name})
-  call assert_equal(['README.txt', 'Readme.txt', 'readme.txt'], files, 'sort by C collation')
-
-  " 6) Collation de_DE
-  " Switch locale, this may not work on the CI system, if the locale isn't
-  " available
-  try
-    lang collate de_DE
-    let files = readdirex('Xsortdir2', 1, #{sort: 'collate'})->map({-> v:val.name})
-    call assert_equal(['readme.txt', 'Readme.txt', 'README.txt'], files, 'sort by de_DE collation')
-  catch
-    throw 'Skipped: de_DE collation is not available'
-
-  finally
-    exe 'lang collate' collate
-  endtry
-endfunc
-
-func Test_readdir_sort()
-  " some more cases for testing sorting for readdirex
-  let dir = 'Xsortdir3'
-  call mkdir(dir, 'R')
-  call writefile(['1'], dir .. '/README.txt')
-  call writefile(['2'], dir .. '/Readm.txt')
-  call writefile(['3'], dir .. '/read.txt')
-  call writefile(['4'], dir .. '/Z.txt')
-  call writefile(['5'], dir .. '/a.txt')
-  call writefile(['6'], dir .. '/b.txt')
-
-  " 1) default
-  let files = readdir(dir)
-  let default = copy(files)
-  call assert_equal(default->sort(), files, 'sort using default')
-
-  " 2) sort by case (same as default)
-  let files = readdir(dir, '1', #{sort: 'case'})
-  call assert_equal(default, files, 'sort using default')
-
-  " 3) sort by ignoring case
-  let files = readdir(dir, '1', #{sort: 'icase'})
-  call assert_equal(default->sort('i'), files, 'sort by ignoring case')
-
-  " 4) collation
-  let collate = v:collate
-  lang collate C
-  let files = readdir(dir, 1, #{sort: 'collate'})
-  call assert_equal(default->sort(), files, 'sort by C collation')
-  exe "lang collate" collate
-
-  " 5) Errors
-  call assert_fails('call readdir(dir, 1, 1)', 'E1206:')
-  call assert_fails('call readdir(dir, 1, #{sorta: 1})')
-  call assert_fails('call readdir(dir, 1, test_null_dict())', 'E1297:')
-  call assert_fails('call readdirex(dir, 1, 1)', 'E1206:')
-  call assert_fails('call readdirex(dir, 1, #{sorta: 1})')
-  call assert_fails('call readdirex(dir, 1, test_null_dict())', 'E1297:')
-
-  " 6) ignore other values in dict
-  let files = readdir(dir, '1', #{sort: 'c'})
-  call assert_equal(default, files, 'sort using default2')
-
-  " Cleanup
-  exe "lang collate" collate
-endfunc
-
-func Test_delete_rf()
-  call mkdir('Xrfdir')
-  call writefile([], 'Xrfdir/foo.txt')
-  call writefile([], 'Xrfdir/bar.txt')
-  call mkdir('Xrfdir/[a-1]')  " issue #696
-  call writefile([], 'Xrfdir/[a-1]/foo.txt')
-  call writefile([], 'Xrfdir/[a-1]/bar.txt')
-  call assert_true(filereadable('Xrfdir/foo.txt'))
-  call assert_true('Xrfdir/[a-1]/foo.txt'->filereadable())
-
-  call assert_equal(0, delete('Xrfdir', 'rf'))
-  call assert_false(filereadable('Xrfdir/foo.txt'))
-  call assert_false(filereadable('Xrfdir/[a-1]/foo.txt'))
-
-  if has('unix')
-    call mkdir('Xrfdir/Xdir2', 'p')
-    silent !chmod 555 Xrfdir
-    call assert_equal(-1, delete('Xrfdir/Xdir2', 'rf'))
-    call assert_equal(-1, delete('Xrfdir', 'rf'))
-    silent !chmod 755 Xrfdir
-    call assert_equal(0, delete('Xrfdir', 'rf'))
-  endif
-endfunc
-
-func Test_call()
-  call assert_equal(3, call('len', [123]))
-  call assert_equal(3, 'len'->call([123]))
-  call assert_fails("call call('len', 123)", 'E1211:')
-  call assert_equal(0, call('', []))
-  call assert_equal(0, call('len', test_null_list()))
-
-  function Mylen() dict
-     return len(self.data)
-  endfunction
-  let mydict = {'data': [0, 1, 2, 3], 'len': function("Mylen")}
-  eval mydict.len->call([], mydict)->assert_equal(4)
-  call assert_fails("call call('Mylen', [], 0)", 'E1206:')
-  call assert_fails('call foo', 'E107:')
-
-  " These once caused a crash.
-  call call(test_null_function(), [])
-  call call(test_null_partial(), [])
-  call assert_fails('call test_null_function()()', 'E1192:')
-  call assert_fails('call test_null_partial()()', 'E117:')
-
-  let lines =<< trim END
-      let Time = 'localtime'
-      call Time()
-  END
-  call v9.CheckScriptFailure(lines, 'E1085:')
-endfunc
-
-func Test_char2nr()
-  call assert_equal(12354, char2nr('あ', 1))
-  call assert_equal(120, 'x'->char2nr())
-  set encoding=latin1
-  call assert_equal(120, 'x'->char2nr())
-  set encoding=utf-8
-endfunc
-
-func Test_charclass()
-  call assert_equal(0, charclass(' '))
-  call assert_equal(1, charclass('.'))
-  call assert_equal(2, charclass('x'))
-  call assert_equal(3, charclass("\u203c"))
-  " this used to crash vim
-  call assert_equal(0, "xxx"[-1]->charclass())
-endfunc
-
-func Test_eventhandler()
-  call assert_equal(0, eventhandler())
-endfunc
-
-func Test_bufadd_bufload()
-  call assert_equal(0, bufexists('someName'))
-  let buf = bufadd('someName')
-  call assert_notequal(0, buf)
-  call assert_equal(1, bufexists('someName'))
-  call assert_equal(0, getbufvar(buf, '&buflisted'))
-  call assert_equal(0, bufloaded(buf))
-  call bufload(buf)
-  call assert_equal(1, bufloaded(buf))
-  call assert_equal([''], getbufline(buf, 1, '$'))
-
-  let curbuf = bufnr('')
-  eval ['some', 'text']->writefile('XotherName')
-  let buf = 'XotherName'->bufadd()
-  call assert_notequal(0, buf)
-  eval 'XotherName'->bufexists()->assert_equal(1)
-  call assert_equal(0, getbufvar(buf, '&buflisted'))
-  call assert_equal(0, bufloaded(buf))
-  eval buf->bufload()
-  call assert_equal(1, bufloaded(buf))
-  call assert_equal(['some', 'text'], getbufline(buf, 1, '$'))
-  call assert_equal(curbuf, bufnr(''))
-
-  let buf1 = bufadd('')
-  let buf2 = bufadd('')
-  call assert_notequal(0, buf1)
-  call assert_notequal(0, buf2)
-  call assert_notequal(buf1, buf2)
-  call assert_equal(1, bufexists(buf1))
-  call assert_equal(1, bufexists(buf2))
-  call assert_equal(0, bufloaded(buf1))
-  exe 'bwipe ' .. buf1
-  call assert_equal(0, bufexists(buf1))
-  call assert_equal(1, bufexists(buf2))
-  exe 'bwipe ' .. buf2
-  call assert_equal(0, bufexists(buf2))
-
-  " When 'buftype' is "nofile" then bufload() does not read the file.
-  " Other values too.
-  for val in [['nofile', 0],
-            \ ['nowrite', 1],
-            \ ['acwrite', 1],
-            \ ['quickfix', 0],
-            \ ['help', 1],
-            \ ['terminal', 0],
-            \ ['prompt', 0],
-            \ ['popup', 0],
-            \ ]
-    bwipe! XotherName
-    let buf = bufadd('XotherName')
-    call setbufvar(buf, '&bt', val[0])
-    call bufload(buf)
-    call assert_equal(val[1] ? ['some', 'text'] : [''], getbufline(buf, 1, '$'), val[0])
-  endfor
-
-  bwipe someName
-  bwipe XotherName
-  call assert_equal(0, bufexists('someName'))
-  call delete('XotherName')
-endfunc
-
-func Test_state()
-  CheckRunVimInTerminal
-
-  let getstate = ":echo 'state: ' .. g:state .. '; mode: ' .. g:mode\<CR>"
-
-  let lines =<< trim END
-	call setline(1, ['one', 'two', 'three'])
-	map ;; gg
-	set complete=.
-	func RunTimer()
-	  call timer_start(10, {id -> execute('let g:state = state()') .. execute('let g:mode = mode()')})
-	endfunc
-	au Filetype foobar let g:state = state()|let g:mode = mode()
-  END
-  call writefile(lines, 'XState')
-  let buf = RunVimInTerminal('-S XState', #{rows: 6})
-
-  " Using a ":" command Vim is busy, thus "S" is returned
-  call term_sendkeys(buf, ":echo 'state: ' .. state() .. '; mode: ' .. mode()\<CR>")
-  call WaitForAssert({-> assert_match('state: S; mode: n', term_getline(buf, 6))}, 1000)
-  call term_sendkeys(buf, ":\<CR>")
-
-  " Using a timer callback
-  call term_sendkeys(buf, ":call RunTimer()\<CR>")
-  call TermWait(buf, 25)
-  call term_sendkeys(buf, getstate)
-  call WaitForAssert({-> assert_match('state: c; mode: n', term_getline(buf, 6))}, 1000)
-
-  " Halfway a mapping
-  call term_sendkeys(buf, ":call RunTimer()\<CR>;")
-  call TermWait(buf, 25)
-  call term_sendkeys(buf, ";")
-  call term_sendkeys(buf, getstate)
-  call WaitForAssert({-> assert_match('state: mSc; mode: n', term_getline(buf, 6))}, 1000)
-
-  " Insert mode completion (bit slower on Mac)
-  call term_sendkeys(buf, ":call RunTimer()\<CR>Got\<C-N>")
-  call TermWait(buf, 25)
-  call term_sendkeys(buf, "\<Esc>")
-  call term_sendkeys(buf, getstate)
-  call WaitForAssert({-> assert_match('state: aSc; mode: i', term_getline(buf, 6))}, 1000)
-
-  " Autocommand executing
-  call term_sendkeys(buf, ":set filetype=foobar\<CR>")
-  call TermWait(buf, 25)
-  call term_sendkeys(buf, getstate)
-  call WaitForAssert({-> assert_match('state: xS; mode: n', term_getline(buf, 6))}, 1000)
-
-  " Todo: "w" - waiting for ch_evalexpr()
-
-  " messages scrolled
-  call term_sendkeys(buf, ":call RunTimer()\<CR>:echo \"one\\ntwo\\nthree\"\<CR>")
-  call TermWait(buf, 25)
-  call term_sendkeys(buf, "\<CR>")
-  call term_sendkeys(buf, getstate)
-  call WaitForAssert({-> assert_match('state: Scs; mode: r', term_getline(buf, 6))}, 1000)
-
-  call StopVimInTerminal(buf)
-  call delete('XState')
-endfunc
-
-func Test_range()
-  " destructuring
-  let [x, y] = range(2)
-  call assert_equal([0, 1], [x, y])
-
-  " index
-  call assert_equal(4, range(1, 10)[3])
-
-  " add()
-  call assert_equal([0, 1, 2, 3], add(range(3), 3))
-  call assert_equal([0, 1, 2, [0, 1, 2]], add([0, 1, 2], range(3)))
-  call assert_equal([0, 1, 2, [0, 1, 2]], add(range(3), range(3)))
-
-  " append()
-  new
-  call append('.', range(5))
-  call assert_equal(['', '0', '1', '2', '3', '4'], getline(1, '$'))
-  bwipe!
-
-  " appendbufline()
-  new
-  call appendbufline(bufnr(''), '.', range(5))
-  call assert_equal(['0', '1', '2', '3', '4', ''], getline(1, '$'))
-  bwipe!
-
-  " call()
-  func TwoArgs(a, b)
-    return [a:a, a:b]
-  endfunc
-  call assert_equal([0, 1], call('TwoArgs', range(2)))
-
-  " col()
-  new
-  call setline(1, ['foo', 'bar'])
-  call assert_equal(2, col(range(1, 2)))
-  bwipe!
-
-  " complete()
-  execute "normal! a\<C-r>=[complete(col('.'), range(10)), ''][1]\<CR>"
-  " complete_info()
-  execute "normal! a\<C-r>=[complete(col('.'), range(10)), ''][1]\<CR>\<C-r>=[complete_info(range(5)), ''][1]\<CR>"
-
-  " copy()
-  call assert_equal([1, 2, 3], copy(range(1, 3)))
-
-  " count()
-  call assert_equal(0, count(range(0), 3))
-  call assert_equal(0, count(range(2), 3))
-  call assert_equal(1, count(range(5), 3))
-
-  " cursor()
-  new
-  call setline(1, ['aaa', 'bbb', 'ccc'])
-  call cursor(range(1, 2))
-  call assert_equal([2, 1], [col('.'), line('.')])
-  bwipe!
-
-  " deepcopy()
-  call assert_equal([1, 2, 3], deepcopy(range(1, 3)))
-
-  " empty()
-  call assert_true(empty(range(0)))
-  call assert_false(empty(range(2)))
-
-  " execute()
-  new
-  call setline(1, ['aaa', 'bbb', 'ccc'])
-  call execute(range(3))
-  call assert_equal(2, line('.'))
-  bwipe!
-
-  " extend()
-  call assert_equal([1, 2, 3, 4], extend([1], range(2, 4)))
-  call assert_equal([1, 2, 3, 4], extend(range(1, 1), range(2, 4)))
-  call assert_equal([1, 2, 3, 4], extend(range(1, 1), [2, 3, 4]))
-
-  " filter()
-  call assert_equal([1, 3], filter(range(5), 'v:val % 2'))
-  call assert_equal([1, 5, 7, 11, 13], filter(filter(range(15), 'v:val % 2'), 'v:val % 3'))
-
-  " funcref()
-  call assert_equal([0, 1], funcref('TwoArgs', range(2))())
-
-  " function()
-  call assert_equal([0, 1], function('TwoArgs', range(2))())
-
-  " garbagecollect()
-  let thelist = [1, range(2), 3]
-  let otherlist = range(3)
-  call test_garbagecollect_now()
-
-  " get()
-  call assert_equal(4, get(range(1, 10), 3))
-  call assert_equal(-1, get(range(1, 10), 42, -1))
-
-  " index()
-  call assert_equal(1, index(range(1, 5), 2))
-  call assert_fails("echo index([1, 2], 1, [])", 'E745:')
-
-  " insert()
-  call assert_equal([42, 1, 2, 3, 4, 5], insert(range(1, 5), 42))
-  call assert_equal([42, 1, 2, 3, 4, 5], insert(range(1, 5), 42, 0))
-  call assert_equal([1, 42, 2, 3, 4, 5], insert(range(1, 5), 42, 1))
-  call assert_equal([1, 2, 3, 4, 42, 5], insert(range(1, 5), 42, 4))
-  call assert_equal([1, 2, 3, 4, 42, 5], insert(range(1, 5), 42, -1))
-  call assert_equal([1, 2, 3, 4, 5, 42], insert(range(1, 5), 42, 5))
-
-  " join()
-  call assert_equal('0 1 2 3 4', join(range(5)))
-
-  " json_encode()
-  call assert_equal('[0,1,2,3]', json_encode(range(4)))
-
-  " len()
-  call assert_equal(0, len(range(0)))
-  call assert_equal(2, len(range(2)))
-  call assert_equal(5, len(range(0, 12, 3)))
-  call assert_equal(4, len(range(3, 0, -1)))
-
-  " list2str()
-  call assert_equal('ABC', list2str(range(65, 67)))
-  call assert_fails('let s = list2str(5)', 'E1211:')
-
-  " lock()
-  let thelist = range(5)
-  lockvar thelist
-
-  " map()
-  call assert_equal([0, 2, 4, 6, 8], map(range(5), 'v:val * 2'))
-  call assert_equal([3, 5, 7, 9, 11], map(map(range(5), 'v:val * 2'), 'v:val + 3'))
-  call assert_equal([2, 6], map(filter(range(5), 'v:val % 2'), 'v:val * 2'))
-  call assert_equal([2, 4, 8], filter(map(range(5), 'v:val * 2'), 'v:val % 3'))
-
-  " match()
-  call assert_equal(3, match(range(5), 3))
-
-  " matchaddpos()
-  highlight MyGreenGroup ctermbg=green guibg=green
-  call matchaddpos('MyGreenGroup', range(line('.'), line('.')))
-
-  " matchend()
-  call assert_equal(4, matchend(range(5), '4'))
-  call assert_equal(3, matchend(range(1, 5), '4'))
-  call assert_equal(-1, matchend(range(1, 5), '42'))
-
-  " matchstrpos()
-  call assert_equal(['4', 4, 0, 1], matchstrpos(range(5), '4'))
-  call assert_equal(['4', 3, 0, 1], matchstrpos(range(1, 5), '4'))
-  call assert_equal(['', -1, -1, -1], matchstrpos(range(1, 5), '42'))
-
-  " max() reverse()
-  call assert_equal(0, max(range(0)))
-  call assert_equal(0, max(range(10, 9)))
-  call assert_equal(9, max(range(10)))
-  call assert_equal(18, max(range(0, 20, 3)))
-  call assert_equal(20, max(range(20, 0, -3)))
-  call assert_equal(99999, max(range(100000)))
-  call assert_equal(99999, max(range(99999, 0, -1)))
-  call assert_equal(99999, max(reverse(range(100000))))
-  call assert_equal(99999, max(reverse(range(99999, 0, -1))))
-
-  " min() reverse()
-  call assert_equal(0, min(range(0)))
-  call assert_equal(0, min(range(10, 9)))
-  call assert_equal(5, min(range(5, 10)))
-  call assert_equal(5, min(range(5, 10, 3)))
-  call assert_equal(2, min(range(20, 0, -3)))
-  call assert_equal(0, min(range(100000)))
-  call assert_equal(0, min(range(99999, 0, -1)))
-  call assert_equal(0, min(reverse(range(100000))))
-  call assert_equal(0, min(reverse(range(99999, 0, -1))))
-
-  " remove()
-  call assert_equal(1, remove(range(1, 10), 0))
-  call assert_equal(2, remove(range(1, 10), 1))
-  call assert_equal(9, remove(range(1, 10), 8))
-  call assert_equal(10, remove(range(1, 10), 9))
-  call assert_equal(10, remove(range(1, 10), -1))
-  call assert_equal([3, 4, 5], remove(range(1, 10), 2, 4))
-
-  " repeat()
-  call assert_equal([0, 1, 2, 0, 1, 2], repeat(range(3), 2))
-  call assert_equal([0, 1, 2], repeat(range(3), 1))
-  call assert_equal([], repeat(range(3), 0))
-  call assert_equal([], repeat(range(5, 4), 2))
-  call assert_equal([], repeat(range(5, 4), 0))
-
-  " reverse()
-  call assert_equal([2, 1, 0], reverse(range(3)))
-  call assert_equal([0, 1, 2, 3], reverse(range(3, 0, -1)))
-  call assert_equal([9, 8, 7, 6, 5, 4, 3, 2, 1, 0], reverse(range(10)))
-  call assert_equal([20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10], reverse(range(10, 20)))
-  call assert_equal([16, 13, 10], reverse(range(10, 18, 3)))
-  call assert_equal([19, 16, 13, 10], reverse(range(10, 19, 3)))
-  call assert_equal([19, 16, 13, 10], reverse(range(10, 20, 3)))
-  call assert_equal([11, 14, 17, 20], reverse(range(20, 10, -3)))
-  call assert_equal([], reverse(range(0)))
-
-  " TODO: setpos()
-  " new
-  " call setline(1, repeat([''], bufnr('')))
-  " call setline(bufnr('') + 1, repeat('x', bufnr('') * 2 + 6))
-  " call setpos('x', range(bufnr(''), bufnr('') + 3))
-  " bwipe!
-
-  " setreg()
-  call setreg('a', range(3))
-  call assert_equal("0\n1\n2\n", getreg('a'))
-
-  " settagstack()
-  call settagstack(1, #{items : range(4)})
-
-  " sign_define()
-  call assert_fails("call sign_define(range(5))", "E715:")
-  call assert_fails("call sign_placelist(range(5))", "E715:")
-
-  " sign_undefine()
-  call assert_fails("call sign_undefine(range(5))", "E908:")
-
-  " sign_unplacelist()
-  call assert_fails("call sign_unplacelist(range(5))", "E715:")
-
-  " sort()
-  call assert_equal([0, 1, 2, 3, 4, 5], sort(range(5, 0, -1)))
-
-  " string()
-  call assert_equal('[0, 1, 2, 3, 4]', string(range(5)))
-
-  " taglist() with 'tagfunc'
-  func TagFunc(pattern, flags, info)
-    return range(10)
-  endfunc
-  set tagfunc=TagFunc
-  call assert_fails("call taglist('asdf')", 'E987:')
-  set tagfunc=
-
-  " term_start()
-  if has('terminal') && has('termguicolors')
-    call assert_fails('call term_start(range(3, 4))', 'E474:')
-    let g:terminal_ansi_colors = range(16)
-    if has('win32')
-      let cmd = "cmd /c dir"
-    else
-      let cmd = "ls"
-    endif
-    call assert_fails('call term_start("' .. cmd .. '", #{term_finish: "close"'
-        \ .. ', ansi_colors: range(16)})', 'E475:')
-    unlet g:terminal_ansi_colors
-  endif
-
-  " type()
-  call assert_equal(v:t_list, type(range(5)))
-
-  " uniq()
-  call assert_equal([0, 1, 2, 3, 4], uniq(range(5)))
-
-  " errors
-  call assert_fails('let x=range(2, 8, 0)', 'E726:')
-  call assert_fails('let x=range(3, 1)', 'E727:')
-  call assert_fails('let x=range(1, 3, -2)', 'E727:')
-  call assert_fails('let x=range([])', 'E745:')
-  call assert_fails('let x=range(1, [])', 'E745:')
-  call assert_fails('let x=range(1, 4, [])', 'E745:')
-endfunc
-
-func Test_garbagecollect_now_fails()
-  let v:testing = 0
-  call assert_fails('call test_garbagecollect_now()', 'E1142:')
-  let v:testing = 1
-endfunc
-
-func Test_echoraw()
-  CheckScreendump
-
-  " Normally used for escape codes, but let's test with a CR.
-  let lines =<< trim END
-    call echoraw("hello\<CR>x")
-  END
-  call writefile(lines, 'XTest_echoraw')
-  let buf = RunVimInTerminal('-S XTest_echoraw', {'rows': 5, 'cols': 40})
-  call VerifyScreenDump(buf, 'Test_functions_echoraw', {})
-
-  " clean up
-  call StopVimInTerminal(buf)
-  call delete('XTest_echoraw')
-endfunc
-
-" Test for echo highlighting
-func Test_echohl()
-  echohl Search
-  echo 'Vim'
-  call assert_equal('Vim', Screenline(&lines))
-  " TODO: How to check the highlight group used by echohl?
-  " ScreenAttrs() returns all zeros.
-  echohl None
-endfunc
-
-" Test for the eval() function
-func Test_eval()
-  call assert_fails("call eval('5 a')", 'E488:')
-endfunc
-
-" Test for the keytrans() function
-func Test_keytrans()
-  call assert_equal('<Space>', keytrans(' '))
-  call assert_equal('<lt>', keytrans('<'))
-  call assert_equal('<lt>Tab>', keytrans('<Tab>'))
-  call assert_equal('<Tab>', keytrans("\<Tab>"))
-  call assert_equal('<C-V>', keytrans("\<C-V>"))
-  call assert_equal('<BS>', keytrans("\<BS>"))
-  call assert_equal('<Home>', keytrans("\<Home>"))
-  call assert_equal('<C-Home>', keytrans("\<C-Home>"))
-  call assert_equal('<M-Home>', keytrans("\<M-Home>"))
-  call assert_equal('<C-Space>', keytrans("\<C-Space>"))
-  call assert_equal('<M-Space>', keytrans("\<*M-Space>"))
-  call assert_equal('<M-x>', "\<*M-x>"->keytrans())
-  call assert_equal('<C-I>', "\<*C-I>"->keytrans())
-  call assert_equal('<S-3>', "\<*S-3>"->keytrans())
-  call assert_equal('π', 'π'->keytrans())
-  call assert_equal('<M-π>', "\<M-π>"->keytrans())
-  call assert_equal('ě', 'ě'->keytrans())
-  call assert_equal('<M-ě>', "\<M-ě>"->keytrans())
-  call assert_equal('', ''->keytrans())
-  call assert_equal('', test_null_string()->keytrans())
-  call assert_fails('call keytrans(1)', 'E1174:')
-  call assert_fails('call keytrans()', 'E119:')
-endfunc
-
-" Test for the nr2char() function
-func Test_nr2char()
-  set encoding=latin1
-  call assert_equal('@', nr2char(64))
-  set encoding=utf8
-  call assert_equal('a', nr2char(97, 1))
-  call assert_equal('a', nr2char(97, 0))
-
-  call assert_equal("\x80\xfc\b" .. nr2char(0x100000), eval('"\<M-' .. nr2char(0x100000) .. '>"'))
-  call assert_equal("\x80\xfc\b" .. nr2char(0x40000000), eval('"\<M-' .. nr2char(0x40000000) .. '>"'))
-endfunc
-
-" Test for screenattr(), screenchar() and screenchars() functions
-func Test_screen_functions()
-  call assert_equal(-1, screenattr(-1, -1))
-  call assert_equal(-1, screenchar(-1, -1))
-  call assert_equal([], screenchars(-1, -1))
-
-  " Run this in a separate Vim instance to avoid messing up.
-  let after =<< trim [CODE]
-    scriptencoding utf-8
-    call setline(1, '口')
-    redraw
-    call assert_equal(0, screenattr(1, 1))
-    call assert_equal(char2nr('口'), screenchar(1, 1))
-    call assert_equal([char2nr('口')], screenchars(1, 1))
-    call assert_equal('口', screenstring(1, 1))
-    call writefile(v:errors, 'Xresult')
-    qall!
-  [CODE]
-
-  let encodings = ['utf-8', 'cp932', 'cp936', 'cp949', 'cp950']
-  if !has('win32')
-    let encodings += ['euc-jp']
-  endif
-  for enc in encodings
-    let msg = 'enc=' .. enc
-    if RunVim([], after, $'--clean --cmd "set encoding={enc}"')
-      call assert_equal([], readfile('Xresult'), msg)
-    endif
-    call delete('Xresult')
-  endfor
-endfunc
-
-" Test for getcurpos() and setpos()
-func Test_getcurpos_setpos()
-  new
-  call setline(1, ['012345678', '012345678'])
-  normal gg6l
-  let sp = getcurpos()
-  normal 0
-  call setpos('.', sp)
-  normal jyl
-  call assert_equal('6', @")
-  call assert_equal(-1, setpos('.', test_null_list()))
-  call assert_equal(-1, setpos('.', {}))
-
-  let winid = win_getid()
-  normal G$
-  let pos = getcurpos()
-  wincmd w
-  call assert_equal(pos, getcurpos(winid))
-
-  wincmd w
-  close!
-
-  call assert_equal(getcurpos(), getcurpos(0))
-  call assert_equal([0, 0, 0, 0, 0], getcurpos(-1))
-  call assert_equal([0, 0, 0, 0, 0], getcurpos(1999))
-endfunc
-
-func Test_getmousepos()
-  enew!
-  call setline(1, "\t\t\t1234")
-  call test_setmouse(1, 1)
-  call assert_equal(#{
-        \ screenrow: 1,
-        \ screencol: 1,
-        \ winid: win_getid(),
-        \ winrow: 1,
-        \ wincol: 1,
-        \ line: 1,
-        \ column: 1,
-        \ }, getmousepos())
-  call test_setmouse(1, 25)
-  call assert_equal(#{
-        \ screenrow: 1,
-        \ screencol: 25,
-        \ winid: win_getid(),
-        \ winrow: 1,
-        \ wincol: 25,
-        \ line: 1,
-        \ column: 4,
-        \ }, getmousepos())
-  call test_setmouse(1, 50)
-  call assert_equal(#{
-        \ screenrow: 1,
-        \ screencol: 50,
-        \ winid: win_getid(),
-        \ winrow: 1,
-        \ wincol: 50,
-        \ line: 1,
-        \ column: 8,
-        \ }, getmousepos())
-
-  " If the mouse is positioned past the last buffer line, "line" and "column"
-  " should act like it's positioned on the last buffer line.
-  call test_setmouse(2, 25)
-  call assert_equal(#{
-        \ screenrow: 2,
-        \ screencol: 25,
-        \ winid: win_getid(),
-        \ winrow: 2,
-        \ wincol: 25,
-        \ line: 1,
-        \ column: 4,
-        \ }, getmousepos())
-  call test_setmouse(2, 50)
-  call assert_equal(#{
-        \ screenrow: 2,
-        \ screencol: 50,
-        \ winid: win_getid(),
-        \ winrow: 2,
-        \ wincol: 50,
-        \ line: 1,
-        \ column: 8,
-        \ }, getmousepos())
-  bwipe!
-endfunc
-
-func Test_getmouseshape()
-  CheckFeature mouseshape
-
-  call assert_equal('arrow', getmouseshape())
-endfunc
-
-" Test for glob()
-func Test_glob()
-  call assert_equal('', glob(test_null_string()))
-  call assert_equal('', globpath(test_null_string(), test_null_string()))
-  call assert_fails("let x = globpath(&rtp, 'syntax/c.vim', [])", 'E745:')
-
-  call writefile([], 'Xglob1')
-  call writefile([], 'XGLOB2')
-  set wildignorecase
-  " Sort output of glob() otherwise we end up with different
-  " ordering depending on whether file system is case-sensitive.
-  call assert_equal(['XGLOB2', 'Xglob1'], sort(glob('Xglob[12]', 0, 1)))
-  " wildignorecase shall be applied even when the pattern contains no wildcards.
-  call assert_equal('XGLOB2', glob('xglob2'))
-  set wildignorecase&
-
-  call delete('Xglob1')
-  call delete('XGLOB2')
-
-  call assert_fails("call glob('*', 0, {})", 'E728:')
-endfunc
-
-" Test for browse()
-func Test_browse()
-  CheckFeature browse
-  call assert_fails('call browse([], "open", "x", "a.c")', 'E745:')
-endfunc
-
-" Test for browsedir()
-func Test_browsedir()
-  CheckFeature browse
-  call assert_fails('call browsedir("open", [])', 'E730:')
-endfunc
-
-func HasDefault(msg = 'msg')
-  return a:msg
-endfunc
-
-func Test_default_arg_value()
-  call assert_equal('msg', HasDefault())
-endfunc
-
-" Test for gettext()
-func Test_gettext()
-  call assert_fails('call gettext(1)', 'E1174:')
-endfunc
-
-func Test_builtin_check()
-  call assert_fails('let g:["trim"] = {x -> " " .. x}', 'E704:')
-  call assert_fails('let g:.trim = {x -> " " .. x}', 'E704:')
-  call assert_fails('let l:["trim"] = {x -> " " .. x}', 'E704:')
-  call assert_fails('let l:.trim = {x -> " " .. x}', 'E704:')
-  let lines =<< trim END
-    vim9script
-    var trim = (x) => " " .. x
-  END
-  call v9.CheckScriptFailure(lines, 'E704:')
-
-  call assert_fails('call extend(g:, #{foo: { -> "foo" }})', 'E704:')
-  let g:bar = 123
-  call extend(g:, #{bar: { -> "foo" }}, "keep")
-  call assert_fails('call extend(g:, #{bar: { -> "foo" }}, "force")', 'E704:')
-  unlet g:bar
-
-  call assert_fails('call extend(l:, #{foo: { -> "foo" }})', 'E704:')
-  let bar = 123
-  call extend(l:, #{bar: { -> "foo" }}, "keep")
-  call assert_fails('call extend(l:, #{bar: { -> "foo" }}, "force")', 'E704:')
-  unlet bar
-
-  call assert_fails('call extend(g:, #{foo: function("extend")})', 'E704:')
-  let g:bar = 123
-  call extend(g:, #{bar: function("extend")}, "keep")
-  call assert_fails('call extend(g:, #{bar: function("extend")}, "force")', 'E704:')
-  unlet g:bar
-
-  call assert_fails('call extend(l:, #{foo: function("extend")})', 'E704:')
-  let bar = 123
-  call extend(l:, #{bar: function("extend")}, "keep")
-  call assert_fails('call extend(l:, #{bar: function("extend")}, "force")', 'E704:')
-  unlet bar
-endfunc
-
-func Test_funcref_to_string()
-  let Fn = funcref('g:Test_funcref_to_string')
-  call assert_equal("function('g:Test_funcref_to_string')", string(Fn))
-endfunc
-
-" Test for isabsolutepath()
-func Test_isabsolutepath()
-  call assert_false(isabsolutepath(''))
-  call assert_false(isabsolutepath('.'))
-  call assert_false(isabsolutepath('../Foo'))
-  call assert_false(isabsolutepath('Foo/'))
-  if has('win32')
-    call assert_true(isabsolutepath('A:\'))
-    call assert_true(isabsolutepath('A:\Foo'))
-    call assert_true(isabsolutepath('A:/Foo'))
-    call assert_false(isabsolutepath('A:Foo'))
-    call assert_false(isabsolutepath('\Windows'))
-    call assert_true(isabsolutepath('\\Server2\Share\Test\Foo.txt'))
-  else
-    call assert_true(isabsolutepath('/'))
-    call assert_true(isabsolutepath('/usr/share/'))
-  endif
-endfunc
-
-" Test for exepath()
-func Test_exepath()
-  if has('win32')
-    call assert_notequal(exepath('cmd'), '')
-
-    let oldNoDefaultCurrentDirectoryInExePath = $NoDefaultCurrentDirectoryInExePath
-    call writefile(['@echo off', 'echo Evil'], 'vim-test-evil.bat')
-    let $NoDefaultCurrentDirectoryInExePath = ''
-    call assert_notequal(exepath("vim-test-evil.bat"), '')
-    let $NoDefaultCurrentDirectoryInExePath = '1'
-    call assert_equal(exepath("vim-test-evil.bat"), '')
-    let $NoDefaultCurrentDirectoryInExePath = oldNoDefaultCurrentDirectoryInExePath
-    call delete('vim-test-evil.bat')
-  else
-    call assert_notequal(exepath('sh'), '')
-  endif
-endfunc
-
-" Test for virtcol()
-func Test_virtcol()
-  enew!
-  call setline(1, "the\tquick\tbrown\tfox")
-  norm! 4|
-  call assert_equal(8, virtcol('.'))
-  call assert_equal(8, virtcol('.', v:false))
-  call assert_equal([4, 8], virtcol('.', v:true))
-  bwipe!
-endfunc
-
-func Test_delfunc_while_listing()
-  CheckRunVimInTerminal
-
-  let lines =<< trim END
-      set nocompatible
-      for i in range(1, 999)
-        exe 'func ' .. 'MyFunc' .. i .. '()'
-        endfunc
-      endfor
-      au CmdlineLeave : call timer_start(0, {-> execute('delfunc MyFunc622')})
-  END
-  call writefile(lines, 'Xfunctionclear', 'D')
-  let buf = RunVimInTerminal('-S Xfunctionclear', {'rows': 12})
-
-  " This was using freed memory.  The height of the terminal must be so that
-  " the next function to be listed with "j" is the one that is deleted in the
-  " timer callback, tricky!
-  call term_sendkeys(buf, ":func /MyFunc\<CR>")
-  call TermWait(buf, 50)
-  call term_sendkeys(buf, "j")
-  call TermWait(buf, 50)
-  call term_sendkeys(buf, "\<CR>")
-
-  call StopVimInTerminal(buf)
-endfunc
-
-" Test for the reverse() function with a string
-func Test_string_reverse()
-  let lines =<< trim END
-    call assert_equal('', reverse(test_null_string()))
-    for [s1, s2] in [['', ''], ['a', 'a'], ['ab', 'ba'], ['abc', 'cba'],
-                   \ ['abcd', 'dcba'], ['«-«-»-»', '»-»-«-«'],
-                   \ ['🇦', '🇦'], ['🇦🇧', '🇧🇦'], ['🇦🇧🇨', '🇨🇧🇦'],
-                   \ ['🇦«🇧-🇨»🇩', '🇩»🇨-🇧«🇦']]
-      call assert_equal(s2, reverse(s1))
-    endfor
-  END
-  call v9.CheckLegacyAndVim9Success(lines)
-
-  " test in latin1 encoding
-  let save_enc = &encoding
-  set encoding=latin1
-  call assert_equal('dcba', reverse('abcd'))
-  let &encoding = save_enc
-endfunc
-
-" vim: shiftwidth=2 sts=2 expandtab
+" Tests for various functions.
+
+source shared.vim
+source check.vim
+source term_util.vim
+source screendump.vim
+import './vim9.vim' as v9
+
+" Must be done first, since the alternate buffer must be unset.
+func Test_00_bufexists()
+  call assert_equal(0, bufexists('does_not_exist'))
+  call assert_equal(1, bufexists(bufnr('%')))
+  call assert_equal(0, bufexists(0))
+  new Xfoo
+  let bn = bufnr('%')
+  call assert_equal(1, bufexists(bn))
+  call assert_equal(1, bufexists('Xfoo'))
+  call assert_equal(1, bufexists(getcwd() . '/Xfoo'))
+  call assert_equal(1, bufexists(0))
+  bw
+  call assert_equal(0, bufexists(bn))
+  call assert_equal(0, bufexists('Xfoo'))
+endfunc
+
+func Test_has()
+  call assert_equal(1, has('eval'))
+  call assert_equal(1, has('eval', 1))
+
+  if has('unix')
+    call assert_equal(1, or(has('ttyin'), 1))
+    call assert_equal(0, and(has('ttyout'), 0))
+    call assert_equal(1, has('multi_byte_encoding'))
+  endif
+  call assert_equal(1, has('vcon', 1))
+  call assert_equal(1, has('mouse_gpm_enabled', 1))
+
+  call assert_equal(0, has('nonexistent'))
+  call assert_equal(0, has('nonexistent', 1))
+
+  " Will we ever have patch 9999?
+  let ver = 'patch-' .. v:version / 100 .. '.' .. v:version % 100 .. '.9999'
+  call assert_equal(0, has(ver))
+
+  " There actually isn't a patch 9.0.0, but this is more consistent.
+  call assert_equal(1, has('patch-9.0.0'))
+endfunc
+
+func Test_empty()
+  call assert_equal(1, empty(''))
+  call assert_equal(0, empty('a'))
+
+  call assert_equal(1, empty(0))
+  call assert_equal(1, empty(-0))
+  call assert_equal(0, empty(1))
+  call assert_equal(0, empty(-1))
+
+  call assert_equal(1, empty(0.0))
+  call assert_equal(1, empty(-0.0))
+  call assert_equal(0, empty(1.0))
+  call assert_equal(0, empty(-1.0))
+  call assert_equal(0, empty(1.0/0.0))
+  call assert_equal(0, empty(0.0/0.0))
+
+  call assert_equal(1, empty([]))
+  call assert_equal(0, empty(['a']))
+
+  call assert_equal(1, empty({}))
+  call assert_equal(0, empty({'a':1}))
+
+  call assert_equal(1, empty(v:null))
+  call assert_equal(1, empty(v:none))
+  call assert_equal(1, empty(v:false))
+  call assert_equal(0, empty(v:true))
+
+  if has('channel')
+    call assert_equal(1, empty(test_null_channel()))
+  endif
+  if has('job')
+    call assert_equal(1, empty(test_null_job()))
+  endif
+
+  call assert_equal(0, empty(function('Test_empty')))
+  call assert_equal(0, empty(function('Test_empty', [0])))
+
+  call assert_fails("call empty(test_void())", ['E340:', 'E685:'])
+  call assert_fails("call empty(test_unknown())", ['E340:', 'E685:'])
+endfunc
+
+func Test_test_void()
+  call assert_fails('echo 1 == test_void()', 'E1031:')
+  call assert_fails('echo 1.0 == test_void()', 'E1031:')
+  call assert_fails('let x = json_encode(test_void())', ['E340:', 'E685:'])
+  call assert_fails('let x = copy(test_void())', ['E340:', 'E685:'])
+  call assert_fails('let x = copy([test_void()])', 'E1031:')
+endfunc
+
+func Test_islocked()
+  call assert_fails('call islocked(99)', 'E475:')
+  call assert_fails('call islocked("s: x")', 'E488:')
+endfunc
+
+func Test_len()
+  call assert_equal(1, len(0))
+  call assert_equal(2, len(12))
+
+  call assert_equal(0, len(''))
+  call assert_equal(2, len('ab'))
+
+  call assert_equal(0, len([]))
+  call assert_equal(0, len(test_null_list()))
+  call assert_equal(2, len([2, 1]))
+
+  call assert_equal(0, len({}))
+  call assert_equal(0, len(test_null_dict()))
+  call assert_equal(2, len({'a': 1, 'b': 2}))
+
+  call assert_fails('call len(v:none)', 'E701:')
+  call assert_fails('call len({-> 0})', 'E701:')
+endfunc
+
+func Test_max()
+  call assert_equal(0, max([]))
+  call assert_equal(2, max([2]))
+  call assert_equal(2, max([1, 2]))
+  call assert_equal(2, max([1, 2, v:null]))
+
+  call assert_equal(0, max({}))
+  call assert_equal(2, max({'a':1, 'b':2}))
+
+  call assert_fails('call max(1)', 'E712:')
+  call assert_fails('call max(v:none)', 'E712:')
+
+  " check we only get one error
+  call assert_fails('call max([#{}, [1]])', ['E728:', 'E728:'])
+  call assert_fails('call max(#{a: {}, b: [1]})', ['E728:', 'E728:'])
+endfunc
+
+func Test_min()
+  call assert_equal(0, min([]))
+  call assert_equal(2, min([2]))
+  call assert_equal(1, min([1, 2]))
+  call assert_equal(0, min([1, 2, v:null]))
+
+  call assert_equal(0, min({}))
+  call assert_equal(1, min({'a':1, 'b':2}))
+
+  call assert_fails('call min(1)', 'E712:')
+  call assert_fails('call min(v:none)', 'E712:')
+  call assert_fails('call min([1, {}])', 'E728:')
+
+  " check we only get one error
+  call assert_fails('call min([[1], #{}])', ['E745:', 'E745:'])
+  call assert_fails('call min(#{a: [1], b: #{}})', ['E745:', 'E745:'])
+endfunc
+
+func Test_strwidth()
+  for aw in ['single', 'double']
+    exe 'set ambiwidth=' . aw
+    call assert_equal(0, strwidth(''))
+    call assert_equal(1, strwidth("\t"))
+    call assert_equal(3, strwidth('Vim'))
+    call assert_equal(4, strwidth(1234))
+    call assert_equal(5, strwidth(-1234))
+
+    call assert_equal(2, strwidth('😉'))
+    call assert_equal(17, strwidth('Eĥoŝanĝo ĉiuĵaŭde'))
+    call assert_equal((aw == 'single') ? 6 : 7, strwidth('Straße'))
+
+    call assert_fails('call strwidth({->0})', 'E729:')
+    call assert_fails('call strwidth([])', 'E730:')
+    call assert_fails('call strwidth({})', 'E731:')
+  endfor
+
+  call assert_equal(3, strwidth(1.2))
+  call v9.CheckDefAndScriptFailure(['echo strwidth(1.2)'], ['E1013: Argument 1: type mismatch, expected string but got float', 'E1174: String required for argument 1'])
+
+  set ambiwidth&
+endfunc
+
+func Test_str2nr()
+  call assert_equal(0, str2nr(''))
+  call assert_equal(1, str2nr('1'))
+  call assert_equal(1, str2nr(' 1 '))
+
+  call assert_equal(1, str2nr('+1'))
+  call assert_equal(1, str2nr('+ 1'))
+  call assert_equal(1, str2nr(' + 1 '))
+
+  call assert_equal(-1, str2nr('-1'))
+  call assert_equal(-1, str2nr('- 1'))
+  call assert_equal(-1, str2nr(' - 1 '))
+
+  call assert_equal(123456789, str2nr('123456789'))
+  call assert_equal(-123456789, str2nr('-123456789'))
+
+  call assert_equal(5, str2nr('101', 2))
+  call assert_equal(5, '0b101'->str2nr(2))
+  call assert_equal(5, str2nr('0B101', 2))
+  call assert_equal(-5, str2nr('-101', 2))
+  call assert_equal(-5, str2nr('-0b101', 2))
+  call assert_equal(-5, str2nr('-0B101', 2))
+
+  call assert_equal(65, str2nr('101', 8))
+  call assert_equal(65, str2nr('0101', 8))
+  call assert_equal(-65, str2nr('-101', 8))
+  call assert_equal(-65, str2nr('-0101', 8))
+  call assert_equal(65, str2nr('0o101', 8))
+  call assert_equal(65, str2nr('0O0101', 8))
+  call assert_equal(-65, str2nr('-0O101', 8))
+  call assert_equal(-65, str2nr('-0o0101', 8))
+
+  call assert_equal(11259375, str2nr('abcdef', 16))
+  call assert_equal(11259375, str2nr('ABCDEF', 16))
+  call assert_equal(-11259375, str2nr('-ABCDEF', 16))
+  call assert_equal(11259375, str2nr('0xabcdef', 16))
+  call assert_equal(11259375, str2nr('0Xabcdef', 16))
+  call assert_equal(11259375, str2nr('0XABCDEF', 16))
+  call assert_equal(-11259375, str2nr('-0xABCDEF', 16))
+
+  call assert_equal(1, str2nr("1'000'000", 10, 0))
+  call assert_equal(256, str2nr("1'0000'0000", 2, 1))
+  call assert_equal(262144, str2nr("1'000'000", 8, 1))
+  call assert_equal(1000000, str2nr("1'000'000", 10, 1))
+  call assert_equal(1000, str2nr("1'000''000", 10, 1))
+  call assert_equal(65536, str2nr("1'00'00", 16, 1))
+
+  call assert_equal(0, str2nr('0x10'))
+  call assert_equal(0, str2nr('0b10'))
+  call assert_equal(0, str2nr('0o10'))
+  call assert_equal(1, str2nr('12', 2))
+  call assert_equal(1, str2nr('18', 8))
+  call assert_equal(1, str2nr('1g', 16))
+
+  call assert_equal(0, str2nr(v:null))
+  call assert_equal(0, str2nr(v:none))
+
+  call assert_fails('call str2nr([])', 'E730:')
+  call assert_fails('call str2nr({->2})', 'E729:')
+  call assert_equal(1, str2nr(1.2))
+  call v9.CheckDefAndScriptFailure(['echo str2nr(1.2)'], ['E1013: Argument 1: type mismatch, expected string but got float', 'E1174: String required for argument 1'])
+  call assert_fails('call str2nr(10, [])', 'E745:')
+endfunc
+
+func Test_strftime()
+  CheckFunction strftime
+
+  " Format of strftime() depends on system. We assume
+  " that basic formats tested here are available and
+  " identical on all systems which support strftime().
+  "
+  " The 2nd parameter of strftime() is a local time, so the output day
+  " of strftime() can be 17 or 18, depending on timezone.
+  call assert_match('^2017-01-1[78]$', strftime('%Y-%m-%d', 1484695512))
+  "
+  call assert_match('^\d\d\d\d-\(0\d\|1[012]\)-\([012]\d\|3[01]\) \([01]\d\|2[0-3]\):[0-5]\d:\([0-5]\d\|60\)$', '%Y-%m-%d %H:%M:%S'->strftime())
+
+  call assert_fails('call strftime([])', 'E730:')
+  call assert_fails('call strftime("%Y", [])', 'E745:')
+
+  " Check that the time changes after we change the timezone
+  " Save previous timezone value, if any
+  if exists('$TZ')
+    let tz = $TZ
+  endif
+
+  " Force EST and then UTC, save the current hour (24-hour clock) for each
+  let $TZ = 'EST' | let est = strftime('%H')
+  let $TZ = 'UTC' | let utc = strftime('%H')
+
+  " Those hours should be two bytes long, and should not be the same; if they
+  " are, a tzset(3) call may have failed somewhere
+  call assert_equal(strlen(est), 2)
+  call assert_equal(strlen(utc), 2)
+  " TODO: this fails on MS-Windows
+  if has('unix')
+    call assert_notequal(est, utc)
+  endif
+
+  " If we cached a timezone value, put it back, otherwise clear it
+  if exists('tz')
+    let $TZ = tz
+  else
+    unlet $TZ
+  endif
+endfunc
+
+func Test_strptime()
+  CheckFunction strptime
+
+  if exists('$TZ')
+    let tz = $TZ
+  endif
+  let $TZ = 'UTC'
+
+  call assert_equal(1484653763, strptime('%Y-%m-%d %T', '2017-01-17 11:49:23'))
+
+  " Force DST and check that it's considered
+  let $TZ = 'WINTER0SUMMER,J1,J365'
+  call assert_equal(1484653763 - 3600, strptime('%Y-%m-%d %T', '2017-01-17 11:49:23'))
+
+  call assert_fails('call strptime()', 'E119:')
+  call assert_fails('call strptime("xxx")', 'E119:')
+  call assert_equal(0, strptime("%Y", ''))
+  call assert_equal(0, strptime("%Y", "xxx"))
+
+  if exists('tz')
+    let $TZ = tz
+  else
+    unlet $TZ
+  endif
+endfunc
+
+func Test_resolve_unix()
+  CheckUnix
+
+  " Xlink1 -> Xlink2
+  " Xlink2 -> Xlink3
+  silent !ln -s -f Xlink2 Xlink1
+  silent !ln -s -f Xlink3 Xlink2
+  call assert_equal('Xlink3', resolve('Xlink1'))
+  call assert_equal('./Xlink3', resolve('./Xlink1'))
+  call assert_equal('Xlink3/', resolve('Xlink2/'))
+  " FIXME: these tests result in things like "Xlink2/" instead of "Xlink3/"?!
+  "call assert_equal('Xlink3/', resolve('Xlink1/'))
+  "call assert_equal('./Xlink3/', resolve('./Xlink1/'))
+  "call assert_equal(getcwd() . '/Xlink3/', resolve(getcwd() . '/Xlink1/'))
+  call assert_equal(getcwd() . '/Xlink3', resolve(getcwd() . '/Xlink1'))
+
+  " Test resolve() with a symlink cycle.
+  " Xlink1 -> Xlink2
+  " Xlink2 -> Xlink3
+  " Xlink3 -> Xlink1
+  silent !ln -s -f Xlink1 Xlink3
+  call assert_fails('call resolve("Xlink1")',   'E655:')
+  call assert_fails('call resolve("./Xlink1")', 'E655:')
+  call assert_fails('call resolve("Xlink2")',   'E655:')
+  call assert_fails('call resolve("Xlink3")',   'E655:')
+  call delete('Xlink1')
+  call delete('Xlink2')
+  call delete('Xlink3')
+
+  silent !ln -s -f Xresolvedir//Xfile Xresolvelink
+  call assert_equal('Xresolvedir/Xfile', resolve('Xresolvelink'))
+  call delete('Xresolvelink')
+
+  silent !ln -s -f Xlink2/ Xlink1
+  call assert_equal('Xlink2', 'Xlink1'->resolve())
+  call assert_equal('Xlink2/', resolve('Xlink1/'))
+  call delete('Xlink1')
+
+  silent !ln -s -f ./Xlink2 Xlink1
+  call assert_equal('Xlink2', resolve('Xlink1'))
+  call assert_equal('./Xlink2', resolve('./Xlink1'))
+  call delete('Xlink1')
+
+  call assert_equal('/', resolve('/'))
+endfunc
+
+func s:normalize_fname(fname)
+  let ret = substitute(a:fname, '\', '/', 'g')
+  let ret = substitute(ret, '//', '/', 'g')
+  return ret->tolower()
+endfunc
+
+func Test_resolve_win32()
+  CheckMSWindows
+
+  " test for shortcut file
+  if executable('cscript')
+    new Xresfile
+    wq
+    let lines =<< trim END
+	Set fs = CreateObject("Scripting.FileSystemObject")
+	Set ws = WScript.CreateObject("WScript.Shell")
+	Set shortcut = ws.CreateShortcut("Xlink.lnk")
+	shortcut.TargetPath = fs.BuildPath(ws.CurrentDirectory, "Xresfile")
+	shortcut.Save
+    END
+    call writefile(lines, 'link.vbs')
+    silent !cscript link.vbs
+    call delete('link.vbs')
+    call assert_equal(s:normalize_fname(getcwd() . '\Xresfile'), s:normalize_fname(resolve('./Xlink.lnk')))
+    call delete('Xresfile')
+
+    call assert_equal(s:normalize_fname(getcwd() . '\Xresfile'), s:normalize_fname(resolve('./Xlink.lnk')))
+    call delete('Xlink.lnk')
+  else
+    echomsg 'skipped test for shortcut file'
+  endif
+
+  " remove files
+  call delete('Xlink')
+  call delete('Xdir', 'd')
+  call delete('Xresfile')
+
+  " test for symbolic link to a file
+  new Xresfile
+  wq
+  call assert_equal('Xresfile', resolve('Xresfile'))
+  silent !mklink Xlink Xresfile
+  if !v:shell_error
+    call assert_equal(s:normalize_fname(getcwd() . '\Xresfile'), s:normalize_fname(resolve('./Xlink')))
+    call delete('Xlink')
+  else
+    echomsg 'skipped test for symbolic link to a file'
+  endif
+  call delete('Xresfile')
+
+  " test for junction to a directory
+  call mkdir('Xdir')
+  silent !mklink /J Xlink Xdir
+  if !v:shell_error
+    call assert_equal(s:normalize_fname(getcwd() . '\Xdir'), s:normalize_fname(resolve(getcwd() . '/Xlink')))
+
+    call delete('Xdir', 'd')
+
+    " test for junction already removed
+    call assert_equal(s:normalize_fname(getcwd() . '\Xlink'), s:normalize_fname(resolve(getcwd() . '/Xlink')))
+    call delete('Xlink')
+  else
+    echomsg 'skipped test for junction to a directory'
+    call delete('Xdir', 'd')
+  endif
+
+  " test for symbolic link to a directory
+  call mkdir('Xdir')
+  silent !mklink /D Xlink Xdir
+  if !v:shell_error
+    call assert_equal(s:normalize_fname(getcwd() . '\Xdir'), s:normalize_fname(resolve(getcwd() . '/Xlink')))
+
+    call delete('Xdir', 'd')
+
+    " test for symbolic link already removed
+    call assert_equal(s:normalize_fname(getcwd() . '\Xlink'), s:normalize_fname(resolve(getcwd() . '/Xlink')))
+    call delete('Xlink')
+  else
+    echomsg 'skipped test for symbolic link to a directory'
+    call delete('Xdir', 'd')
+  endif
+
+  " test for buffer name
+  new Xbuffile
+  wq
+  silent !mklink Xlink Xbuffile
+  if !v:shell_error
+    edit Xlink
+    call assert_equal('Xlink', bufname('%'))
+    call delete('Xlink')
+    bw!
+  else
+    echomsg 'skipped test for buffer name'
+  endif
+  call delete('Xbuffile')
+
+  " test for reparse point
+  call mkdir('Xdir')
+  call assert_equal('Xdir', resolve('Xdir'))
+  silent !mklink /D Xdirlink Xdir
+  if !v:shell_error
+    w Xdir/text.txt
+    call assert_equal('Xdir/text.txt', resolve('Xdir/text.txt'))
+    call assert_equal(s:normalize_fname(getcwd() . '\Xdir\text.txt'), s:normalize_fname(resolve('Xdirlink\text.txt')))
+    call assert_equal(s:normalize_fname(getcwd() . '\Xdir'), s:normalize_fname(resolve('Xdirlink')))
+    call delete('Xdirlink')
+  else
+    echomsg 'skipped test for reparse point'
+  endif
+
+  call delete('Xdir', 'rf')
+endfunc
+
+func Test_simplify()
+  call assert_equal('',            simplify(''))
+  call assert_equal('/',           simplify('/'))
+  call assert_equal('/',           simplify('/.'))
+  call assert_equal('/',           simplify('/..'))
+  call assert_equal('/...',        simplify('/...'))
+  call assert_equal('//path',      simplify('//path'))
+  if has('unix')
+    call assert_equal('/path',       simplify('///path'))
+    call assert_equal('/path',       simplify('////path'))
+  endif
+
+  call assert_equal('./dir/file',  './dir/file'->simplify())
+  call assert_equal('./dir/file',  simplify('.///dir//file'))
+  call assert_equal('./dir/file',  simplify('./dir/./file'))
+  call assert_equal('./file',      simplify('./dir/../file'))
+  call assert_equal('../dir/file', simplify('dir/../../dir/file'))
+  call assert_equal('./file',      simplify('dir/.././file'))
+  call assert_equal('../dir',      simplify('./../dir'))
+  call assert_equal('..',          simplify('../testdir/..'))
+  call mkdir('Xsimpdir')
+  call assert_equal('.',           simplify('Xsimpdir/../.'))
+  call delete('Xsimpdir', 'd')
+
+  call assert_fails('call simplify({->0})', 'E729:')
+  call assert_fails('call simplify([])', 'E730:')
+  call assert_fails('call simplify({})', 'E731:')
+  call assert_equal('1.2', simplify(1.2))
+  call v9.CheckDefAndScriptFailure(['echo simplify(1.2)'], ['E1013: Argument 1: type mismatch, expected string but got float', 'E1174: String required for argument 1'])
+endfunc
+
+func Test_pathshorten()
+  call assert_equal('', pathshorten(''))
+  call assert_equal('foo', pathshorten('foo'))
+  call assert_equal('/foo', '/foo'->pathshorten())
+  call assert_equal('f/', pathshorten('foo/'))
+  call assert_equal('f/bar', pathshorten('foo/bar'))
+  call assert_equal('f/b/foobar', 'foo/bar/foobar'->pathshorten())
+  call assert_equal('/f/b/foobar', pathshorten('/foo/bar/foobar'))
+  call assert_equal('.f/bar', pathshorten('.foo/bar'))
+  call assert_equal('~f/bar', pathshorten('~foo/bar'))
+  call assert_equal('~.f/bar', pathshorten('~.foo/bar'))
+  call assert_equal('.~f/bar', pathshorten('.~foo/bar'))
+  call assert_equal('~/f/bar', pathshorten('~/foo/bar'))
+  call assert_fails('call pathshorten([])', 'E730:')
+
+  " test pathshorten with optional variable to set preferred size of shortening
+  call assert_equal('', pathshorten('', 2))
+  call assert_equal('foo', pathshorten('foo', 2))
+  call assert_equal('/foo', pathshorten('/foo', 2))
+  call assert_equal('fo/', pathshorten('foo/', 2))
+  call assert_equal('fo/bar', pathshorten('foo/bar', 2))
+  call assert_equal('fo/ba/foobar', pathshorten('foo/bar/foobar', 2))
+  call assert_equal('/fo/ba/foobar', pathshorten('/foo/bar/foobar', 2))
+  call assert_equal('.fo/bar', pathshorten('.foo/bar', 2))
+  call assert_equal('~fo/bar', pathshorten('~foo/bar', 2))
+  call assert_equal('~.fo/bar', pathshorten('~.foo/bar', 2))
+  call assert_equal('.~fo/bar', pathshorten('.~foo/bar', 2))
+  call assert_equal('~/fo/bar', pathshorten('~/foo/bar', 2))
+  call assert_fails('call pathshorten([],2)', 'E730:')
+  call assert_notequal('~/fo/bar', pathshorten('~/foo/bar', 3))
+  call assert_equal('~/foo/bar', pathshorten('~/foo/bar', 3))
+  call assert_equal('~/f/bar', pathshorten('~/foo/bar', 0))
+endfunc
+
+func Test_strpart()
+  call assert_equal('de', strpart('abcdefg', 3, 2))
+  call assert_equal('ab', strpart('abcdefg', -2, 4))
+  call assert_equal('abcdefg', 'abcdefg'->strpart(-2))
+  call assert_equal('fg', strpart('abcdefg', 5, 4))
+  call assert_equal('defg', strpart('abcdefg', 3))
+  call assert_equal('', strpart('abcdefg', 10))
+  call assert_fails("let s=strpart('abcdef', [])", 'E745:')
+
+  call assert_equal('lép', strpart('éléphant', 2, 4))
+  call assert_equal('léphant', strpart('éléphant', 2))
+
+  call assert_equal('é', strpart('éléphant', 0, 1, 1))
+  call assert_equal('ép', strpart('éléphant', 3, 2, v:true))
+  call assert_equal('ó', strpart('cómposed', 1, 1, 1))
+endfunc
+
+func Test_tolower()
+  call assert_equal("", tolower(""))
+
+  " Test with all printable ASCII characters.
+  call assert_equal(' !"#$%&''()*+,-./0123456789:;<=>?@abcdefghijklmnopqrstuvwxyz[\]^_`abcdefghijklmnopqrstuvwxyz{|}~',
+          \ tolower(' !"#$%&''()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~'))
+
+  " Test with a few uppercase diacritics.
+  call assert_equal("aàáâãäåāăąǎǟǡả", tolower("AÀÁÂÃÄÅĀĂĄǍǞǠẢ"))
+  call assert_equal("bḃḇ", tolower("BḂḆ"))
+  call assert_equal("cçćĉċč", tolower("CÇĆĈĊČ"))
+  call assert_equal("dďđḋḏḑ", tolower("DĎĐḊḎḐ"))
+  call assert_equal("eèéêëēĕėęěẻẽ", tolower("EÈÉÊËĒĔĖĘĚẺẼ"))
+  call assert_equal("fḟ ", tolower("FḞ "))
+  call assert_equal("gĝğġģǥǧǵḡ", tolower("GĜĞĠĢǤǦǴḠ"))
+  call assert_equal("hĥħḣḧḩ", tolower("HĤĦḢḦḨ"))
+  call assert_equal("iìíîïĩīĭįiǐỉ", tolower("IÌÍÎÏĨĪĬĮİǏỈ"))
+  call assert_equal("jĵ", tolower("JĴ"))
+  call assert_equal("kķǩḱḵ", tolower("KĶǨḰḴ"))
+  call assert_equal("lĺļľŀłḻ", tolower("LĹĻĽĿŁḺ"))
+  call assert_equal("mḿṁ", tolower("MḾṀ"))
+  call assert_equal("nñńņňṅṉ", tolower("NÑŃŅŇṄṈ"))
+  call assert_equal("oòóôõöøōŏőơǒǫǭỏ", tolower("OÒÓÔÕÖØŌŎŐƠǑǪǬỎ"))
+  call assert_equal("pṕṗ", tolower("PṔṖ"))
+  call assert_equal("q", tolower("Q"))
+  call assert_equal("rŕŗřṙṟ", tolower("RŔŖŘṘṞ"))
+  call assert_equal("sśŝşšṡ", tolower("SŚŜŞŠṠ"))
+  call assert_equal("tţťŧṫṯ", tolower("TŢŤŦṪṮ"))
+  call assert_equal("uùúûüũūŭůűųưǔủ", tolower("UÙÚÛÜŨŪŬŮŰŲƯǓỦ"))
+  call assert_equal("vṽ", tolower("VṼ"))
+  call assert_equal("wŵẁẃẅẇ", tolower("WŴẀẂẄẆ"))
+  call assert_equal("xẋẍ", tolower("XẊẌ"))
+  call assert_equal("yýŷÿẏỳỷỹ", tolower("YÝŶŸẎỲỶỸ"))
+  call assert_equal("zźżžƶẑẕ", tolower("ZŹŻŽƵẐẔ"))
+
+  " Test with a few lowercase diacritics, which should remain unchanged.
+  call assert_equal("aàáâãäåāăąǎǟǡả", tolower("aàáâãäåāăąǎǟǡả"))
+  call assert_equal("bḃḇ", tolower("bḃḇ"))
+  call assert_equal("cçćĉċč", tolower("cçćĉċč"))
+  call assert_equal("dďđḋḏḑ", tolower("dďđḋḏḑ"))
+  call assert_equal("eèéêëēĕėęěẻẽ", tolower("eèéêëēĕėęěẻẽ"))
+  call assert_equal("fḟ", tolower("fḟ"))
+  call assert_equal("gĝğġģǥǧǵḡ", tolower("gĝğġģǥǧǵḡ"))
+  call assert_equal("hĥħḣḧḩẖ", tolower("hĥħḣḧḩẖ"))
+  call assert_equal("iìíîïĩīĭįǐỉ", tolower("iìíîïĩīĭįǐỉ"))
+  call assert_equal("jĵǰ", tolower("jĵǰ"))
+  call assert_equal("kķǩḱḵ", tolower("kķǩḱḵ"))
+  call assert_equal("lĺļľŀłḻ", tolower("lĺļľŀłḻ"))
+  call assert_equal("mḿṁ ", tolower("mḿṁ "))
+  call assert_equal("nñńņňʼnṅṉ", tolower("nñńņňʼnṅṉ"))
+  call assert_equal("oòóôõöøōŏőơǒǫǭỏ", tolower("oòóôõöøōŏőơǒǫǭỏ"))
+  call assert_equal("pṕṗ", tolower("pṕṗ"))
+  call assert_equal("q", tolower("q"))
+  call assert_equal("rŕŗřṙṟ", tolower("rŕŗřṙṟ"))
+  call assert_equal("sśŝşšṡ", tolower("sśŝşšṡ"))
+  call assert_equal("tţťŧṫṯẗ", tolower("tţťŧṫṯẗ"))
+  call assert_equal("uùúûüũūŭůűųưǔủ", tolower("uùúûüũūŭůűųưǔủ"))
+  call assert_equal("vṽ", tolower("vṽ"))
+  call assert_equal("wŵẁẃẅẇẘ", tolower("wŵẁẃẅẇẘ"))
+  call assert_equal("ẋẍ", tolower("ẋẍ"))
+  call assert_equal("yýÿŷẏẙỳỷỹ", tolower("yýÿŷẏẙỳỷỹ"))
+  call assert_equal("zźżžƶẑẕ", tolower("zźżžƶẑẕ"))
+
+  " According to https://twitter.com/jifa/status/625776454479970304
+  " Ⱥ (U+023A) and Ⱦ (U+023E) are the *only* code points to increase
+  " in length (2 to 3 bytes) when lowercased. So let's test them.
+  call assert_equal("ⱥ ⱦ", tolower("Ⱥ Ⱦ"))
+
+  " This call to tolower with invalid utf8 sequence used to cause access to
+  " invalid memory.
+  call tolower("\xC0\x80\xC0")
+  call tolower("123\xC0\x80\xC0")
+
+  " Test in latin1 encoding
+  let save_enc = &encoding
+  set encoding=latin1
+  call assert_equal("abc", tolower("ABC"))
+  let &encoding = save_enc
+endfunc
+
+func Test_toupper()
+  call assert_equal("", toupper(""))
+
+  " Test with all printable ASCII characters.
+  call assert_equal(' !"#$%&''()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`ABCDEFGHIJKLMNOPQRSTUVWXYZ{|}~',
+          \ toupper(' !"#$%&''()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~'))
+
+  " Test with a few lowercase diacritics.
+  call assert_equal("AÀÁÂÃÄÅĀĂĄǍǞǠẢ", "aàáâãäåāăąǎǟǡả"->toupper())
+  call assert_equal("BḂḆ", toupper("bḃḇ"))
+  call assert_equal("CÇĆĈĊČ", toupper("cçćĉċč"))
+  call assert_equal("DĎĐḊḎḐ", toupper("dďđḋḏḑ"))
+  call assert_equal("EÈÉÊËĒĔĖĘĚẺẼ", toupper("eèéêëēĕėęěẻẽ"))
+  call assert_equal("FḞ", toupper("fḟ"))
+  call assert_equal("GĜĞĠĢǤǦǴḠ", toupper("gĝğġģǥǧǵḡ"))
+  call assert_equal("HĤĦḢḦḨẖ", toupper("hĥħḣḧḩẖ"))
+  call assert_equal("IÌÍÎÏĨĪĬĮǏỈ", toupper("iìíîïĩīĭįǐỉ"))
+  call assert_equal("JĴǰ", toupper("jĵǰ"))
+  call assert_equal("KĶǨḰḴ", toupper("kķǩḱḵ"))
+  call assert_equal("LĹĻĽĿŁḺ", toupper("lĺļľŀłḻ"))
+  call assert_equal("MḾṀ ", toupper("mḿṁ "))
+  call assert_equal("NÑŃŅŇʼnṄṈ", toupper("nñńņňʼnṅṉ"))
+  call assert_equal("OÒÓÔÕÖØŌŎŐƠǑǪǬỎ", toupper("oòóôõöøōŏőơǒǫǭỏ"))
+  call assert_equal("PṔṖ", toupper("pṕṗ"))
+  call assert_equal("Q", toupper("q"))
+  call assert_equal("RŔŖŘṘṞ", toupper("rŕŗřṙṟ"))
+  call assert_equal("SŚŜŞŠṠ", toupper("sśŝşšṡ"))
+  call assert_equal("TŢŤŦṪṮẗ", toupper("tţťŧṫṯẗ"))
+  call assert_equal("UÙÚÛÜŨŪŬŮŰŲƯǓỦ", toupper("uùúûüũūŭůűųưǔủ"))
+  call assert_equal("VṼ", toupper("vṽ"))
+  call assert_equal("WŴẀẂẄẆẘ", toupper("wŵẁẃẅẇẘ"))
+  call assert_equal("ẊẌ", toupper("ẋẍ"))
+  call assert_equal("YÝŸŶẎẙỲỶỸ", toupper("yýÿŷẏẙỳỷỹ"))
+  call assert_equal("ZŹŻŽƵẐẔ", toupper("zźżžƶẑẕ"))
+
+  " Test that uppercase diacritics, which should remain unchanged.
+  call assert_equal("AÀÁÂÃÄÅĀĂĄǍǞǠẢ", toupper("AÀÁÂÃÄÅĀĂĄǍǞǠẢ"))
+  call assert_equal("BḂḆ", toupper("BḂḆ"))
+  call assert_equal("CÇĆĈĊČ", toupper("CÇĆĈĊČ"))
+  call assert_equal("DĎĐḊḎḐ", toupper("DĎĐḊḎḐ"))
+  call assert_equal("EÈÉÊËĒĔĖĘĚẺẼ", toupper("EÈÉÊËĒĔĖĘĚẺẼ"))
+  call assert_equal("FḞ ", toupper("FḞ "))
+  call assert_equal("GĜĞĠĢǤǦǴḠ", toupper("GĜĞĠĢǤǦǴḠ"))
+  call assert_equal("HĤĦḢḦḨ", toupper("HĤĦḢḦḨ"))
+  call assert_equal("IÌÍÎÏĨĪĬĮİǏỈ", toupper("IÌÍÎÏĨĪĬĮİǏỈ"))
+  call assert_equal("JĴ", toupper("JĴ"))
+  call assert_equal("KĶǨḰḴ", toupper("KĶǨḰḴ"))
+  call assert_equal("LĹĻĽĿŁḺ", toupper("LĹĻĽĿŁḺ"))
+  call assert_equal("MḾṀ", toupper("MḾṀ"))
+  call assert_equal("NÑŃŅŇṄṈ", toupper("NÑŃŅŇṄṈ"))
+  call assert_equal("OÒÓÔÕÖØŌŎŐƠǑǪǬỎ", toupper("OÒÓÔÕÖØŌŎŐƠǑǪǬỎ"))
+  call assert_equal("PṔṖ", toupper("PṔṖ"))
+  call assert_equal("Q", toupper("Q"))
+  call assert_equal("RŔŖŘṘṞ", toupper("RŔŖŘṘṞ"))
+  call assert_equal("SŚŜŞŠṠ", toupper("SŚŜŞŠṠ"))
+  call assert_equal("TŢŤŦṪṮ", toupper("TŢŤŦṪṮ"))
+  call assert_equal("UÙÚÛÜŨŪŬŮŰŲƯǓỦ", toupper("UÙÚÛÜŨŪŬŮŰŲƯǓỦ"))
+  call assert_equal("VṼ", toupper("VṼ"))
+  call assert_equal("WŴẀẂẄẆ", toupper("WŴẀẂẄẆ"))
+  call assert_equal("XẊẌ", toupper("XẊẌ"))
+  call assert_equal("YÝŶŸẎỲỶỸ", toupper("YÝŶŸẎỲỶỸ"))
+  call assert_equal("ZŹŻŽƵẐẔ", toupper("ZŹŻŽƵẐẔ"))
+
+  call assert_equal("Ⱥ Ⱦ", toupper("ⱥ ⱦ"))
+
+  " This call to toupper with invalid utf8 sequence used to cause access to
+  " invalid memory.
+  call toupper("\xC0\x80\xC0")
+  call toupper("123\xC0\x80\xC0")
+
+  " Test in latin1 encoding
+  let save_enc = &encoding
+  set encoding=latin1
+  call assert_equal("ABC", toupper("abc"))
+  let &encoding = save_enc
+endfunc
+
+func Test_tr()
+  call assert_equal('foo', tr('bar', 'bar', 'foo'))
+  call assert_equal('zxy', 'cab'->tr('abc', 'xyz'))
+  call assert_fails("let s=tr([], 'abc', 'def')", 'E730:')
+  call assert_fails("let s=tr('abc', [], 'def')", 'E730:')
+  call assert_fails("let s=tr('abc', 'abc', [])", 'E730:')
+  call assert_fails("let s=tr('abcd', 'abcd', 'def')", 'E475:')
+  set encoding=latin1
+  call assert_fails("let s=tr('abcd', 'abcd', 'def')", 'E475:')
+  call assert_equal('hEllO', tr('hello', 'eo', 'EO'))
+  call assert_equal('hello', tr('hello', 'xy', 'ab'))
+  call assert_fails('call tr("abc", "123", "₁₂")', 'E475:')
+  set encoding=utf8
+endfunc
+
+" Tests for the mode() function
+let current_modes = ''
+func Save_mode()
+  let g:current_modes = mode(0) . '-' . mode(1)
+  return ''
+endfunc
+
+" Test for the mode() function
+func Test_mode()
+  new
+  call append(0, ["Blue Ball Black", "Brown Band Bowl", ""])
+
+  " Only complete from the current buffer.
+  set complete=.
+
+  inoremap <F2> <C-R>=Save_mode()<CR>
+  xnoremap <F2> <Cmd>call Save_mode()<CR>
+
+  normal! 3G
+  exe "normal i\<F2>\<Esc>"
+  call assert_equal('i-i', g:current_modes)
+  " i_CTRL-P: Multiple matches
+  exe "normal i\<C-G>uBa\<C-P>\<F2>\<Esc>u"
+  call assert_equal('i-ic', g:current_modes)
+  " i_CTRL-P: Single match
+  exe "normal iBro\<C-P>\<F2>\<Esc>u"
+  call assert_equal('i-ic', g:current_modes)
+  " i_CTRL-X
+  exe "normal iBa\<C-X>\<F2>\<Esc>u"
+  call assert_equal('i-ix', g:current_modes)
+  " i_CTRL-X CTRL-P: Multiple matches
+  exe "normal iBa\<C-X>\<C-P>\<F2>\<Esc>u"
+  call assert_equal('i-ic', g:current_modes)
+  " i_CTRL-X CTRL-P: Single match
+  exe "normal iBro\<C-X>\<C-P>\<F2>\<Esc>u"
+  call assert_equal('i-ic', g:current_modes)
+  " i_CTRL-X CTRL-P + CTRL-P: Single match
+  exe "normal iBro\<C-X>\<C-P>\<C-P>\<F2>\<Esc>u"
+  call assert_equal('i-ic', g:current_modes)
+  " i_CTRL-X CTRL-L: Multiple matches
+  exe "normal i\<C-X>\<C-L>\<F2>\<Esc>u"
+  call assert_equal('i-ic', g:current_modes)
+  " i_CTRL-X CTRL-L: Single match
+  exe "normal iBlu\<C-X>\<C-L>\<F2>\<Esc>u"
+  call assert_equal('i-ic', g:current_modes)
+  " i_CTRL-P: No match
+  exe "normal iCom\<C-P>\<F2>\<Esc>u"
+  call assert_equal('i-ic', g:current_modes)
+  " i_CTRL-X CTRL-P: No match
+  exe "normal iCom\<C-X>\<C-P>\<F2>\<Esc>u"
+  call assert_equal('i-ic', g:current_modes)
+  " i_CTRL-X CTRL-L: No match
+  exe "normal iabc\<C-X>\<C-L>\<F2>\<Esc>u"
+  call assert_equal('i-ic', g:current_modes)
+
+  exe "normal R\<F2>\<Esc>"
+  call assert_equal('R-R', g:current_modes)
+  " R_CTRL-P: Multiple matches
+  exe "normal RBa\<C-P>\<F2>\<Esc>u"
+  call assert_equal('R-Rc', g:current_modes)
+  " R_CTRL-P: Single match
+  exe "normal RBro\<C-P>\<F2>\<Esc>u"
+  call assert_equal('R-Rc', g:current_modes)
+  " R_CTRL-X
+  exe "normal RBa\<C-X>\<F2>\<Esc>u"
+  call assert_equal('R-Rx', g:current_modes)
+  " R_CTRL-X CTRL-P: Multiple matches
+  exe "normal RBa\<C-X>\<C-P>\<F2>\<Esc>u"
+  call assert_equal('R-Rc', g:current_modes)
+  " R_CTRL-X CTRL-P: Single match
+  exe "normal RBro\<C-X>\<C-P>\<F2>\<Esc>u"
+  call assert_equal('R-Rc', g:current_modes)
+  " R_CTRL-X CTRL-P + CTRL-P: Single match
+  exe "normal RBro\<C-X>\<C-P>\<C-P>\<F2>\<Esc>u"
+  call assert_equal('R-Rc', g:current_modes)
+  " R_CTRL-X CTRL-L: Multiple matches
+  exe "normal R\<C-X>\<C-L>\<F2>\<Esc>u"
+  call assert_equal('R-Rc', g:current_modes)
+  " R_CTRL-X CTRL-L: Single match
+  exe "normal RBlu\<C-X>\<C-L>\<F2>\<Esc>u"
+  call assert_equal('R-Rc', g:current_modes)
+  " R_CTRL-P: No match
+  exe "normal RCom\<C-P>\<F2>\<Esc>u"
+  call assert_equal('R-Rc', g:current_modes)
+  " R_CTRL-X CTRL-P: No match
+  exe "normal RCom\<C-X>\<C-P>\<F2>\<Esc>u"
+  call assert_equal('R-Rc', g:current_modes)
+  " R_CTRL-X CTRL-L: No match
+  exe "normal Rabc\<C-X>\<C-L>\<F2>\<Esc>u"
+  call assert_equal('R-Rc', g:current_modes)
+
+  exe "normal gR\<F2>\<Esc>"
+  call assert_equal('R-Rv', g:current_modes)
+  " gR_CTRL-P: Multiple matches
+  exe "normal gRBa\<C-P>\<F2>\<Esc>u"
+  call assert_equal('R-Rvc', g:current_modes)
+  " gR_CTRL-P: Single match
+  exe "normal gRBro\<C-P>\<F2>\<Esc>u"
+  call assert_equal('R-Rvc', g:current_modes)
+  " gR_CTRL-X
+  exe "normal gRBa\<C-X>\<F2>\<Esc>u"
+  call assert_equal('R-Rvx', g:current_modes)
+  " gR_CTRL-X CTRL-P: Multiple matches
+  exe "normal gRBa\<C-X>\<C-P>\<F2>\<Esc>u"
+  call assert_equal('R-Rvc', g:current_modes)
+  " gR_CTRL-X CTRL-P: Single match
+  exe "normal gRBro\<C-X>\<C-P>\<F2>\<Esc>u"
+  call assert_equal('R-Rvc', g:current_modes)
+  " gR_CTRL-X CTRL-P + CTRL-P: Single match
+  exe "normal gRBro\<C-X>\<C-P>\<C-P>\<F2>\<Esc>u"
+  call assert_equal('R-Rvc', g:current_modes)
+  " gR_CTRL-X CTRL-L: Multiple matches
+  exe "normal gR\<C-X>\<C-L>\<F2>\<Esc>u"
+  call assert_equal('R-Rvc', g:current_modes)
+  " gR_CTRL-X CTRL-L: Single match
+  exe "normal gRBlu\<C-X>\<C-L>\<F2>\<Esc>u"
+  call assert_equal('R-Rvc', g:current_modes)
+  " gR_CTRL-P: No match
+  exe "normal gRCom\<C-P>\<F2>\<Esc>u"
+  call assert_equal('R-Rvc', g:current_modes)
+  " gR_CTRL-X CTRL-P: No match
+  exe "normal gRCom\<C-X>\<C-P>\<F2>\<Esc>u"
+  call assert_equal('R-Rvc', g:current_modes)
+  " gR_CTRL-X CTRL-L: No match
+  exe "normal gRabc\<C-X>\<C-L>\<F2>\<Esc>u"
+  call assert_equal('R-Rvc', g:current_modes)
+
+  call assert_equal('n', 0->mode())
+  call assert_equal('n', 1->mode())
+
+  " i_CTRL-O
+  exe "normal i\<C-O>:call Save_mode()\<Cr>\<Esc>"
+  call assert_equal("n-niI", g:current_modes)
+
+  " R_CTRL-O
+  exe "normal R\<C-O>:call Save_mode()\<Cr>\<Esc>"
+  call assert_equal("n-niR", g:current_modes)
+
+  " gR_CTRL-O
+  exe "normal gR\<C-O>:call Save_mode()\<Cr>\<Esc>"
+  call assert_equal("n-niV", g:current_modes)
+
+  " How to test operator-pending mode?
+
+  call feedkeys("v", 'xt')
+  call assert_equal('v', mode())
+  call assert_equal('v', mode(1))
+  call feedkeys("\<Esc>V", 'xt')
+  call assert_equal('V', mode())
+  call assert_equal('V', mode(1))
+  call feedkeys("\<Esc>\<C-V>", 'xt')
+  call assert_equal("\<C-V>", mode())
+  call assert_equal("\<C-V>", mode(1))
+  call feedkeys("\<Esc>", 'xt')
+
+  call feedkeys("gh", 'xt')
+  call assert_equal('s', mode())
+  call assert_equal('s', mode(1))
+  call feedkeys("\<Esc>gH", 'xt')
+  call assert_equal('S', mode())
+  call assert_equal('S', mode(1))
+  call feedkeys("\<Esc>g\<C-H>", 'xt')
+  call assert_equal("\<C-S>", mode())
+  call assert_equal("\<C-S>", mode(1))
+  call feedkeys("\<Esc>", 'xt')
+
+  " v_CTRL-O
+  exe "normal gh\<C-O>\<F2>\<Esc>"
+  call assert_equal("v-vs", g:current_modes)
+  exe "normal gH\<C-O>\<F2>\<Esc>"
+  call assert_equal("V-Vs", g:current_modes)
+  exe "normal g\<C-H>\<C-O>\<F2>\<Esc>"
+  call assert_equal("\<C-V>-\<C-V>s", g:current_modes)
+
+  call feedkeys(":echo \<C-R>=Save_mode()\<C-U>\<CR>", 'xt')
+  call assert_equal('c-c', g:current_modes)
+  call feedkeys("gQecho \<C-R>=Save_mode()\<CR>\<CR>vi\<CR>", 'xt')
+  call assert_equal('c-cv', g:current_modes)
+  call feedkeys("Qcall Save_mode()\<CR>vi\<CR>", 'xt')
+  call assert_equal('c-ce', g:current_modes)
+  " How to test Ex mode?
+
+  " Test mode in operatorfunc (it used to be Operator-pending).
+  set operatorfunc=OperatorFunc
+  function OperatorFunc(_)
+    call Save_mode()
+  endfunction
+  execute "normal! g@l\<Esc>"
+  call assert_equal('n-n', g:current_modes)
+  execute "normal! i\<C-o>g@l\<Esc>"
+  call assert_equal('n-niI', g:current_modes)
+  execute "normal! R\<C-o>g@l\<Esc>"
+  call assert_equal('n-niR', g:current_modes)
+  execute "normal! gR\<C-o>g@l\<Esc>"
+  call assert_equal('n-niV', g:current_modes)
+
+  if has('terminal')
+    term
+    call feedkeys("\<C-W>N", 'xt')
+    call assert_equal('n', mode())
+    call assert_equal('nt', mode(1))
+    call feedkeys("aexit\<CR>", 'xt')
+  endif
+
+  bwipe!
+  iunmap <F2>
+  xunmap <F2>
+  set complete&
+  set operatorfunc&
+  delfunction OperatorFunc
+endfunc
+
+" Test for append()
+func Test_append()
+  enew!
+  split
+  call assert_equal(0, append(1, []))
+  call assert_equal(0, append(1, test_null_list()))
+  call assert_equal(0, append(0, ["foo"]))
+  call assert_equal(0, append(1, []))
+  call assert_equal(0, append(1, test_null_list()))
+  call assert_equal(0, append(8, []))
+  call assert_equal(0, append(9, test_null_list()))
+  call assert_equal(['foo', ''], getline(1, '$'))
+  split
+  only
+  undo
+  undo
+
+  " Using $ instead of '$' must give an error
+  call assert_fails("call append($, 'foobar')", 'E116:')
+
+  call assert_fails("call append({}, '')", ['E728:', 'E728:'])
+endfunc
+
+" Test for setline()
+func Test_setline()
+  new
+  call setline(0, ["foo"])
+  call setline(0, [])
+  call setline(0, test_null_list())
+  call setline(1, ["bar"])
+  call setline(1, [])
+  call setline(1, test_null_list())
+  call setline(2, [])
+  call setline(2, test_null_list())
+  call setline(3, [])
+  call setline(3, test_null_list())
+  call setline(2, ["baz"])
+  call assert_equal(['bar', 'baz'], getline(1, '$'))
+  close!
+endfunc
+
+func Test_getbufvar()
+  let bnr = bufnr('%')
+  let b:var_num = '1234'
+  let def_num = '5678'
+  call assert_equal('1234', getbufvar(bnr, 'var_num'))
+  call assert_equal('1234', getbufvar(bnr, 'var_num', def_num))
+
+  let bd = getbufvar(bnr, '')
+  call assert_equal('1234', bd['var_num'])
+  call assert_true(exists("bd['changedtick']"))
+  call assert_equal(2, len(bd))
+
+  let bd2 = getbufvar(bnr, '', def_num)
+  call assert_equal(bd, bd2)
+
+  unlet b:var_num
+  call assert_equal(def_num, getbufvar(bnr, 'var_num', def_num))
+  call assert_equal('', getbufvar(bnr, 'var_num'))
+
+  let bd = getbufvar(bnr, '')
+  call assert_equal(1, len(bd))
+  let bd = getbufvar(bnr, '',def_num)
+  call assert_equal(1, len(bd))
+
+  call assert_equal('', getbufvar(9999, ''))
+  call assert_equal(def_num, getbufvar(9999, '', def_num))
+  unlet def_num
+
+  call assert_equal(0, getbufvar(bnr, '&autoindent'))
+  call assert_equal(0, getbufvar(bnr, '&autoindent', 1))
+
+  " Set and get a buffer-local variable
+  call setbufvar(bnr, 'bufvar_test', ['one', 'two'])
+  call assert_equal(['one', 'two'], getbufvar(bnr, 'bufvar_test'))
+
+  " Open new window with forced option values
+  set fileformats=unix,dos
+  new ++ff=dos ++bin ++enc=iso-8859-2
+  call assert_equal('dos', getbufvar(bufnr('%'), '&fileformat'))
+  call assert_equal(1, getbufvar(bufnr('%'), '&bin'))
+  call assert_equal('iso-8859-2', getbufvar(bufnr('%'), '&fenc'))
+  close
+
+  " Get the b: dict.
+  let b:testvar = 'one'
+  new
+  let b:testvar = 'two'
+  let thebuf = bufnr()
+  wincmd w
+  call assert_equal('two', getbufvar(thebuf, 'testvar'))
+  call assert_equal('two', getbufvar(thebuf, '').testvar)
+  bwipe!
+
+  set fileformats&
+endfunc
+
+func Test_last_buffer_nr()
+  call assert_equal(bufnr('$'), last_buffer_nr())
+endfunc
+
+func Test_stridx()
+  call assert_equal(-1, stridx('', 'l'))
+  call assert_equal(0,  stridx('', ''))
+  call assert_equal(0,  'hello'->stridx(''))
+  call assert_equal(-1, stridx('hello', 'L'))
+  call assert_equal(2,  stridx('hello', 'l', -1))
+  call assert_equal(2,  stridx('hello', 'l', 0))
+  call assert_equal(2,  'hello'->stridx('l', 1))
+  call assert_equal(3,  stridx('hello', 'l', 3))
+  call assert_equal(-1, stridx('hello', 'l', 4))
+  call assert_equal(-1, stridx('hello', 'l', 10))
+  call assert_equal(2,  stridx('hello', 'll'))
+  call assert_equal(-1, stridx('hello', 'hello world'))
+  call assert_fails("let n=stridx('hello', [])", 'E730:')
+  call assert_fails("let n=stridx([], 'l')", 'E730:')
+endfunc
+
+func Test_strridx()
+  call assert_equal(-1, strridx('', 'l'))
+  call assert_equal(0,  strridx('', ''))
+  call assert_equal(5,  strridx('hello', ''))
+  call assert_equal(-1, strridx('hello', 'L'))
+  call assert_equal(3,  'hello'->strridx('l'))
+  call assert_equal(3,  strridx('hello', 'l', 10))
+  call assert_equal(3,  strridx('hello', 'l', 3))
+  call assert_equal(2,  strridx('hello', 'l', 2))
+  call assert_equal(-1, strridx('hello', 'l', 1))
+  call assert_equal(-1, strridx('hello', 'l', 0))
+  call assert_equal(-1, strridx('hello', 'l', -1))
+  call assert_equal(2,  strridx('hello', 'll'))
+  call assert_equal(-1, strridx('hello', 'hello world'))
+  call assert_fails("let n=strridx('hello', [])", 'E730:')
+  call assert_fails("let n=strridx([], 'l')", 'E730:')
+endfunc
+
+func Test_match_func()
+  call assert_equal(4,  match('testing', 'ing'))
+  call assert_equal(4,  'testing'->match('ing', 2))
+  call assert_equal(-1, match('testing', 'ing', 5))
+  call assert_equal(-1, match('testing', 'ing', 8))
+  call assert_equal(1, match(['vim', 'testing', 'execute'], 'ing'))
+  call assert_equal(-1, match(['vim', 'testing', 'execute'], 'img'))
+  call assert_fails("let x=match('vim', [])", 'E730:')
+  call assert_equal(3, match(['a', 'b', 'c', 'a'], 'a', 1))
+  call assert_equal(-1, match(['a', 'b', 'c', 'a'], 'a', 5))
+  call assert_equal(4,  match('testing', 'ing', -1))
+  call assert_fails("let x=match('testing', 'ing', 0, [])", 'E745:')
+  call assert_equal(-1, match(test_null_list(), 2))
+  call assert_equal(-1, match('abc', '\\%('))
+endfunc
+
+func Test_matchend()
+  call assert_equal(7,  matchend('testing', 'ing'))
+  call assert_equal(7,  'testing'->matchend('ing', 2))
+  call assert_equal(-1, matchend('testing', 'ing', 5))
+  call assert_equal(-1, matchend('testing', 'ing', 8))
+  call assert_equal(match(['vim', 'testing', 'execute'], 'ing'), matchend(['vim', 'testing', 'execute'], 'ing'))
+  call assert_equal(match(['vim', 'testing', 'execute'], 'img'), matchend(['vim', 'testing', 'execute'], 'img'))
+endfunc
+
+func Test_matchlist()
+  call assert_equal(['acd', 'a', '', 'c', 'd', '', '', '', '', ''],  matchlist('acd', '\(a\)\?\(b\)\?\(c\)\?\(.*\)'))
+  call assert_equal(['d', '', '', '', 'd', '', '', '', '', ''],  'acd'->matchlist('\(a\)\?\(b\)\?\(c\)\?\(.*\)', 2))
+  call assert_equal([],  matchlist('acd', '\(a\)\?\(b\)\?\(c\)\?\(.*\)', 4))
+endfunc
+
+func Test_matchstr()
+  call assert_equal('ing',  matchstr('testing', 'ing'))
+  call assert_equal('ing',  'testing'->matchstr('ing', 2))
+  call assert_equal('', matchstr('testing', 'ing', 5))
+  call assert_equal('', matchstr('testing', 'ing', 8))
+  call assert_equal('testing', matchstr(['vim', 'testing', 'execute'], 'ing'))
+  call assert_equal('', matchstr(['vim', 'testing', 'execute'], 'img'))
+endfunc
+
+func Test_matchstrpos()
+  call assert_equal(['ing', 4, 7], matchstrpos('testing', 'ing'))
+  call assert_equal(['ing', 4, 7], 'testing'->matchstrpos('ing', 2))
+  call assert_equal(['', -1, -1], matchstrpos('testing', 'ing', 5))
+  call assert_equal(['', -1, -1], matchstrpos('testing', 'ing', 8))
+  call assert_equal(['ing', 1, 4, 7], matchstrpos(['vim', 'testing', 'execute'], 'ing'))
+  call assert_equal(['', -1, -1, -1], matchstrpos(['vim', 'testing', 'execute'], 'img'))
+  call assert_equal(['', -1, -1], matchstrpos(test_null_list(), '\a'))
+endfunc
+
+func Test_nextnonblank_prevnonblank()
+  new
+insert
+This
+
+
+is
+
+a
+Test
+.
+  call assert_equal(0, nextnonblank(-1))
+  call assert_equal(0, nextnonblank(0))
+  call assert_equal(1, nextnonblank(1))
+  call assert_equal(4, 2->nextnonblank())
+  call assert_equal(4, nextnonblank(3))
+  call assert_equal(4, nextnonblank(4))
+  call assert_equal(6, nextnonblank(5))
+  call assert_equal(6, nextnonblank(6))
+  call assert_equal(7, nextnonblank(7))
+  call assert_equal(0, 8->nextnonblank())
+
+  call assert_equal(0, prevnonblank(-1))
+  call assert_equal(0, prevnonblank(0))
+  call assert_equal(1, 1->prevnonblank())
+  call assert_equal(1, prevnonblank(2))
+  call assert_equal(1, prevnonblank(3))
+  call assert_equal(4, prevnonblank(4))
+  call assert_equal(4, 5->prevnonblank())
+  call assert_equal(6, prevnonblank(6))
+  call assert_equal(7, prevnonblank(7))
+  call assert_equal(0, prevnonblank(8))
+  bw!
+endfunc
+
+func Test_byte2line_line2byte()
+  new
+  set endofline
+  call setline(1, ['a', 'bc', 'd'])
+
+  set fileformat=unix
+  call assert_equal([-1, -1, 1, 1, 2, 2, 2, 3, 3, -1],
+  \                 map(range(-1, 8), 'byte2line(v:val)'))
+  call assert_equal([-1, -1, 1, 3, 6, 8, -1],
+  \                 map(range(-1, 5), 'line2byte(v:val)'))
+
+  set fileformat=mac
+  call assert_equal([-1, -1, 1, 1, 2, 2, 2, 3, 3, -1],
+  \                 map(range(-1, 8), 'v:val->byte2line()'))
+  call assert_equal([-1, -1, 1, 3, 6, 8, -1],
+  \                 map(range(-1, 5), 'v:val->line2byte()'))
+
+  set fileformat=dos
+  call assert_equal([-1, -1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, -1],
+  \                 map(range(-1, 11), 'byte2line(v:val)'))
+  call assert_equal([-1, -1, 1, 4, 8, 11, -1],
+  \                 map(range(-1, 5), 'line2byte(v:val)'))
+
+  bw!
+  set noendofline nofixendofline
+  normal a-
+  for ff in ["unix", "mac", "dos"]
+    let &fileformat = ff
+    call assert_equal(1, line2byte(1))
+    call assert_equal(2, line2byte(2))  " line2byte(line("$") + 1) is the buffer size plus one (as per :help line2byte).
+  endfor
+
+  set endofline& fixendofline& fileformat&
+  bw!
+endfunc
+
+" Test for byteidx() using a character index
+func Test_byteidx()
+  let a = '.é.' " one char of two bytes
+  call assert_equal(0, byteidx(a, 0))
+  call assert_equal(1, byteidx(a, 1))
+  call assert_equal(3, byteidx(a, 2))
+  call assert_equal(4, byteidx(a, 3))
+  call assert_equal(-1, byteidx(a, 4))
+
+  let b = '.é.' " normal e with composing char
+  call assert_equal(0, b->byteidx(0))
+  call assert_equal(1, b->byteidx(1))
+  call assert_equal(4, b->byteidx(2))
+  call assert_equal(5, b->byteidx(3))
+  call assert_equal(-1, b->byteidx(4))
+
+  " string with multiple composing characters
+  let str = '-ą́-ą́'
+  call assert_equal(0, byteidx(str, 0))
+  call assert_equal(1, byteidx(str, 1))
+  call assert_equal(6, byteidx(str, 2))
+  call assert_equal(7, byteidx(str, 3))
+  call assert_equal(12, byteidx(str, 4))
+  call assert_equal(-1, byteidx(str, 5))
+
+  " empty string
+  call assert_equal(0, byteidx('', 0))
+  call assert_equal(-1, byteidx('', 1))
+
+  " error cases
+  call assert_fails("call byteidx([], 0)", 'E730:')
+  call assert_fails("call byteidx('abc', [])", 'E745:')
+  call assert_fails("call byteidx('abc', 0, {})", ['E728:', 'E728:'])
+  call assert_fails("call byteidx('abc', 0, -1)", ['E1023:', 'E1023:'])
+endfunc
+
+" Test for byteidxcomp() using a character index
+func Test_byteidxcomp()
+  let a = '.é.' " one char of two bytes
+  call assert_equal(0, byteidxcomp(a, 0))
+  call assert_equal(1, byteidxcomp(a, 1))
+  call assert_equal(3, byteidxcomp(a, 2))
+  call assert_equal(4, byteidxcomp(a, 3))
+  call assert_equal(-1, byteidxcomp(a, 4))
+
+  let b = '.é.' " normal e with composing char
+  call assert_equal(0, b->byteidxcomp(0))
+  call assert_equal(1, b->byteidxcomp(1))
+  call assert_equal(2, b->byteidxcomp(2))
+  call assert_equal(4, b->byteidxcomp(3))
+  call assert_equal(5, b->byteidxcomp(4))
+  call assert_equal(-1, b->byteidxcomp(5))
+
+  " string with multiple composing characters
+  let str = '-ą́-ą́'
+  call assert_equal(0, byteidxcomp(str, 0))
+  call assert_equal(1, byteidxcomp(str, 1))
+  call assert_equal(2, byteidxcomp(str, 2))
+  call assert_equal(4, byteidxcomp(str, 3))
+  call assert_equal(6, byteidxcomp(str, 4))
+  call assert_equal(7, byteidxcomp(str, 5))
+  call assert_equal(8, byteidxcomp(str, 6))
+  call assert_equal(10, byteidxcomp(str, 7))
+  call assert_equal(12, byteidxcomp(str, 8))
+  call assert_equal(-1, byteidxcomp(str, 9))
+
+  " empty string
+  call assert_equal(0, byteidxcomp('', 0))
+  call assert_equal(-1, byteidxcomp('', 1))
+
+  " error cases
+  call assert_fails("call byteidxcomp([], 0)", 'E730:')
+  call assert_fails("call byteidxcomp('abc', [])", 'E745:')
+  call assert_fails("call byteidxcomp('abc', 0, {})", ['E728:', 'E728:'])
+  call assert_fails("call byteidxcomp('abc', 0, -1)", ['E1023:', 'E1023:'])
+endfunc
+
+" Test for byteidx() using a UTF-16 index
+func Test_byteidx_from_utf16_index()
+  " string with single byte characters
+  let str = "abc"
+  for i in range(3)
+    call assert_equal(i, byteidx(str, i, v:true))
+  endfor
+  call assert_equal(3, byteidx(str, 3, v:true))
+  call assert_equal(-1, byteidx(str, 4, v:true))
+
+  " string with two byte characters
+  let str = "a©©b"
+  call assert_equal(0, byteidx(str, 0, v:true))
+  call assert_equal(1, byteidx(str, 1, v:true))
+  call assert_equal(3, byteidx(str, 2, v:true))
+  call assert_equal(5, byteidx(str, 3, v:true))
+  call assert_equal(6, byteidx(str, 4, v:true))
+  call assert_equal(-1, byteidx(str, 5, v:true))
+
+  " string with two byte characters
+  let str = "a😊😊b"
+  call assert_equal(0, byteidx(str, 0, v:true))
+  call assert_equal(1, byteidx(str, 1, v:true))
+  call assert_equal(1, byteidx(str, 2, v:true))
+  call assert_equal(5, byteidx(str, 3, v:true))
+  call assert_equal(5, byteidx(str, 4, v:true))
+  call assert_equal(9, byteidx(str, 5, v:true))
+  call assert_equal(10, byteidx(str, 6, v:true))
+  call assert_equal(-1, byteidx(str, 7, v:true))
+
+  " string with composing characters
+  let str = '-á-b́'
+  call assert_equal(0, byteidx(str, 0, v:true))
+  call assert_equal(1, byteidx(str, 1, v:true))
+  call assert_equal(4, byteidx(str, 2, v:true))
+  call assert_equal(5, byteidx(str, 3, v:true))
+  call assert_equal(8, byteidx(str, 4, v:true))
+  call assert_equal(-1, byteidx(str, 5, v:true))
+
+  " string with multiple composing characters
+  let str = '-ą́-ą́'
+  call assert_equal(0, byteidx(str, 0, v:true))
+  call assert_equal(1, byteidx(str, 1, v:true))
+  call assert_equal(6, byteidx(str, 2, v:true))
+  call assert_equal(7, byteidx(str, 3, v:true))
+  call assert_equal(12, byteidx(str, 4, v:true))
+  call assert_equal(-1, byteidx(str, 5, v:true))
+
+  " empty string
+  call assert_equal(0, byteidx('', 0, v:true))
+  call assert_equal(-1, byteidx('', 1, v:true))
+
+  " error cases
+  call assert_fails('call byteidx(str, 0, [])', 'E745:')
+endfunc
+
+" Test for byteidxcomp() using a UTF-16 index
+func Test_byteidxcomp_from_utf16_index()
+  " string with single byte characters
+  let str = "abc"
+  for i in range(3)
+    call assert_equal(i, byteidxcomp(str, i, v:true))
+  endfor
+  call assert_equal(3, byteidxcomp(str, 3, v:true))
+  call assert_equal(-1, byteidxcomp(str, 4, v:true))
+
+  " string with two byte characters
+  let str = "a©©b"
+  call assert_equal(0, byteidxcomp(str, 0, v:true))
+  call assert_equal(1, byteidxcomp(str, 1, v:true))
+  call assert_equal(3, byteidxcomp(str, 2, v:true))
+  call assert_equal(5, byteidxcomp(str, 3, v:true))
+  call assert_equal(6, byteidxcomp(str, 4, v:true))
+  call assert_equal(-1, byteidxcomp(str, 5, v:true))
+
+  " string with two byte characters
+  let str = "a😊😊b"
+  call assert_equal(0, byteidxcomp(str, 0, v:true))
+  call assert_equal(1, byteidxcomp(str, 1, v:true))
+  call assert_equal(1, byteidxcomp(str, 2, v:true))
+  call assert_equal(5, byteidxcomp(str, 3, v:true))
+  call assert_equal(5, byteidxcomp(str, 4, v:true))
+  call assert_equal(9, byteidxcomp(str, 5, v:true))
+  call assert_equal(10, byteidxcomp(str, 6, v:true))
+  call assert_equal(-1, byteidxcomp(str, 7, v:true))
+
+  " string with composing characters
+  let str = '-á-b́'
+  call assert_equal(0, byteidxcomp(str, 0, v:true))
+  call assert_equal(1, byteidxcomp(str, 1, v:true))
+  call assert_equal(2, byteidxcomp(str, 2, v:true))
+  call assert_equal(4, byteidxcomp(str, 3, v:true))
+  call assert_equal(5, byteidxcomp(str, 4, v:true))
+  call assert_equal(6, byteidxcomp(str, 5, v:true))
+  call assert_equal(8, byteidxcomp(str, 6, v:true))
+  call assert_equal(-1, byteidxcomp(str, 7, v:true))
+  call assert_fails('call byteidxcomp(str, 0, [])', 'E745:')
+
+  " string with multiple composing characters
+  let str = '-ą́-ą́'
+  call assert_equal(0, byteidxcomp(str, 0, v:true))
+  call assert_equal(1, byteidxcomp(str, 1, v:true))
+  call assert_equal(2, byteidxcomp(str, 2, v:true))
+  call assert_equal(4, byteidxcomp(str, 3, v:true))
+  call assert_equal(6, byteidxcomp(str, 4, v:true))
+  call assert_equal(7, byteidxcomp(str, 5, v:true))
+  call assert_equal(8, byteidxcomp(str, 6, v:true))
+  call assert_equal(10, byteidxcomp(str, 7, v:true))
+  call assert_equal(12, byteidxcomp(str, 8, v:true))
+  call assert_equal(-1, byteidxcomp(str, 9, v:true))
+
+  " empty string
+  call assert_equal(0, byteidxcomp('', 0, v:true))
+  call assert_equal(-1, byteidxcomp('', 1, v:true))
+
+  " error cases
+  call assert_fails('call byteidxcomp(str, 0, [])', 'E745:')
+endfunc
+
+" Test for charidx() using a byte index
+func Test_charidx()
+  let a = 'xáb́y'
+  call assert_equal(0, charidx(a, 0))
+  call assert_equal(1, charidx(a, 3))
+  call assert_equal(2, charidx(a, 4))
+  call assert_equal(3, charidx(a, 7))
+  call assert_equal(4, charidx(a, 8))
+  call assert_equal(-1, charidx(a, 9))
+  call assert_equal(-1, charidx(a, -1))
+
+  " count composing characters
+  call assert_equal(0, a->charidx(0, 1))
+  call assert_equal(2, a->charidx(2, 1))
+  call assert_equal(3, a->charidx(4, 1))
+  call assert_equal(5, a->charidx(7, 1))
+  call assert_equal(6, a->charidx(8, 1))
+  call assert_equal(-1, a->charidx(9, 1))
+
+  " empty string
+  call assert_equal(0, charidx('', 0))
+  call assert_equal(-1, charidx('', 1))
+  call assert_equal(0, charidx('', 0, 1))
+  call assert_equal(-1, charidx('', 1, 1))
+
+  " error cases
+  call assert_equal(0, charidx(test_null_string(), 0))
+  call assert_equal(-1, charidx(test_null_string(), 1))
+  call assert_fails('let x = charidx([], 1)', 'E1174:')
+  call assert_fails('let x = charidx("abc", [])', 'E1210:')
+  call assert_fails('let x = charidx("abc", 1, [])', 'E1212:')
+  call assert_fails('let x = charidx("abc", 1, -1)', 'E1212:')
+  call assert_fails('let x = charidx("abc", 1, 2)', 'E1212:')
+endfunc
+
+" Test for charidx() using a UTF-16 index
+func Test_charidx_from_utf16_index()
+  " string with single byte characters
+  let str = "abc"
+  for i in range(4)
+    call assert_equal(i, charidx(str, i, v:false, v:true))
+  endfor
+  call assert_equal(-1, charidx(str, 4, v:false, v:true))
+
+  " string with two byte characters
+  let str = "a©©b"
+  call assert_equal(0, charidx(str, 0, v:false, v:true))
+  call assert_equal(1, charidx(str, 1, v:false, v:true))
+  call assert_equal(2, charidx(str, 2, v:false, v:true))
+  call assert_equal(3, charidx(str, 3, v:false, v:true))
+  call assert_equal(4, charidx(str, 4, v:false, v:true))
+  call assert_equal(-1, charidx(str, 5, v:false, v:true))
+
+  " string with four byte characters
+  let str = "a😊😊b"
+  call assert_equal(0, charidx(str, 0, v:false, v:true))
+  call assert_equal(1, charidx(str, 1, v:false, v:true))
+  call assert_equal(1, charidx(str, 2, v:false, v:true))
+  call assert_equal(2, charidx(str, 3, v:false, v:true))
+  call assert_equal(2, charidx(str, 4, v:false, v:true))
+  call assert_equal(3, charidx(str, 5, v:false, v:true))
+  call assert_equal(4, charidx(str, 6, v:false, v:true))
+  call assert_equal(-1, charidx(str, 7, v:false, v:true))
+
+  " string with composing characters
+  let str = '-á-b́'
+  for i in str->strcharlen()->range()
+    call assert_equal(i, charidx(str, i, v:false, v:true))
+  endfor
+  call assert_equal(4, charidx(str, 4, v:false, v:true))
+  call assert_equal(-1, charidx(str, 5, v:false, v:true))
+  for i in str->strchars()->range()
+    call assert_equal(i, charidx(str, i, v:true, v:true))
+  endfor
+  call assert_equal(6, charidx(str, 6, v:true, v:true))
+  call assert_equal(-1, charidx(str, 7, v:true, v:true))
+
+  " string with multiple composing characters
+  let str = '-ą́-ą́'
+  for i in str->strcharlen()->range()
+    call assert_equal(i, charidx(str, i, v:false, v:true))
+  endfor
+  call assert_equal(4, charidx(str, 4, v:false, v:true))
+  call assert_equal(-1, charidx(str, 5, v:false, v:true))
+  for i in str->strchars()->range()
+    call assert_equal(i, charidx(str, i, v:true, v:true))
+  endfor
+  call assert_equal(8, charidx(str, 8, v:true, v:true))
+  call assert_equal(-1, charidx(str, 9, v:true, v:true))
+
+  " empty string
+  call assert_equal(0, charidx('', 0, v:false, v:true))
+  call assert_equal(-1, charidx('', 1, v:false, v:true))
+  call assert_equal(0, charidx('', 0, v:true, v:true))
+  call assert_equal(-1, charidx('', 1, v:true, v:true))
+
+  " error cases
+  call assert_equal(0, charidx('', 0, v:false, v:true))
+  call assert_equal(-1, charidx('', 1, v:false, v:true))
+  call assert_equal(0, charidx('', 0, v:true, v:true))
+  call assert_equal(-1, charidx('', 1, v:true, v:true))
+  call assert_equal(0, charidx(test_null_string(), 0, v:false, v:true))
+  call assert_equal(-1, charidx(test_null_string(), 1, v:false, v:true))
+  call assert_fails('let x = charidx("abc", 1, v:false, [])', 'E1212:')
+  call assert_fails('let x = charidx("abc", 1, v:true, [])', 'E1212:')
+endfunc
+
+" Test for utf16idx() using a byte index
+func Test_utf16idx_from_byteidx()
+  " UTF-16 index of a string with single byte characters
+  let str = "abc"
+  for i in range(4)
+    call assert_equal(i, utf16idx(str, i))
+  endfor
+  call assert_equal(-1, utf16idx(str, 4))
+
+  " UTF-16 index of a string with two byte characters
+  let str = 'a©©b'
+  call assert_equal(0, str->utf16idx(0))
+  call assert_equal(1, str->utf16idx(1))
+  call assert_equal(1, str->utf16idx(2))
+  call assert_equal(2, str->utf16idx(3))
+  call assert_equal(2, str->utf16idx(4))
+  call assert_equal(3, str->utf16idx(5))
+  call assert_equal(4, str->utf16idx(6))
+  call assert_equal(-1, str->utf16idx(7))
+
+  " UTF-16 index of a string with four byte characters
+  let str = 'a😊😊b'
+  call assert_equal(0, utf16idx(str, 0))
+  call assert_equal(1, utf16idx(str, 1))
+  call assert_equal(1, utf16idx(str, 2))
+  call assert_equal(1, utf16idx(str, 3))
+  call assert_equal(1, utf16idx(str, 4))
+  call assert_equal(3, utf16idx(str, 5))
+  call assert_equal(3, utf16idx(str, 6))
+  call assert_equal(3, utf16idx(str, 7))
+  call assert_equal(3, utf16idx(str, 8))
+  call assert_equal(5, utf16idx(str, 9))
+  call assert_equal(6, utf16idx(str, 10))
+  call assert_equal(-1, utf16idx(str, 11))
+
+  " UTF-16 index of a string with composing characters
+  let str = '-á-b́'
+  call assert_equal(0, utf16idx(str, 0))
+  call assert_equal(1, utf16idx(str, 1))
+  call assert_equal(1, utf16idx(str, 2))
+  call assert_equal(1, utf16idx(str, 3))
+  call assert_equal(2, utf16idx(str, 4))
+  call assert_equal(3, utf16idx(str, 5))
+  call assert_equal(3, utf16idx(str, 6))
+  call assert_equal(3, utf16idx(str, 7))
+  call assert_equal(4, utf16idx(str, 8))
+  call assert_equal(-1, utf16idx(str, 9))
+  call assert_equal(0, utf16idx(str, 0, v:true))
+  call assert_equal(1, utf16idx(str, 1, v:true))
+  call assert_equal(2, utf16idx(str, 2, v:true))
+  call assert_equal(2, utf16idx(str, 3, v:true))
+  call assert_equal(3, utf16idx(str, 4, v:true))
+  call assert_equal(4, utf16idx(str, 5, v:true))
+  call assert_equal(5, utf16idx(str, 6, v:true))
+  call assert_equal(5, utf16idx(str, 7, v:true))
+  call assert_equal(6, utf16idx(str, 8, v:true))
+  call assert_equal(-1, utf16idx(str, 9, v:true))
+
+  " string with multiple composing characters
+  let str = '-ą́-ą́'
+  call assert_equal(0, utf16idx(str, 0))
+  call assert_equal(1, utf16idx(str, 1))
+  call assert_equal(1, utf16idx(str, 2))
+  call assert_equal(1, utf16idx(str, 3))
+  call assert_equal(1, utf16idx(str, 4))
+  call assert_equal(1, utf16idx(str, 5))
+  call assert_equal(2, utf16idx(str, 6))
+  call assert_equal(3, utf16idx(str, 7))
+  call assert_equal(3, utf16idx(str, 8))
+  call assert_equal(3, utf16idx(str, 9))
+  call assert_equal(3, utf16idx(str, 10))
+  call assert_equal(3, utf16idx(str, 11))
+  call assert_equal(4, utf16idx(str, 12))
+  call assert_equal(-1, utf16idx(str, 13))
+  call assert_equal(0, utf16idx(str, 0, v:true))
+  call assert_equal(1, utf16idx(str, 1, v:true))
+  call assert_equal(2, utf16idx(str, 2, v:true))
+  call assert_equal(2, utf16idx(str, 3, v:true))
+  call assert_equal(3, utf16idx(str, 4, v:true))
+  call assert_equal(3, utf16idx(str, 5, v:true))
+  call assert_equal(4, utf16idx(str, 6, v:true))
+  call assert_equal(5, utf16idx(str, 7, v:true))
+  call assert_equal(6, utf16idx(str, 8, v:true))
+  call assert_equal(6, utf16idx(str, 9, v:true))
+  call assert_equal(7, utf16idx(str, 10, v:true))
+  call assert_equal(7, utf16idx(str, 11, v:true))
+  call assert_equal(8, utf16idx(str, 12, v:true))
+  call assert_equal(-1, utf16idx(str, 13, v:true))
+
+  " empty string
+  call assert_equal(0, utf16idx('', 0))
+  call assert_equal(-1, utf16idx('', 1))
+  call assert_equal(0, utf16idx('', 0, v:true))
+  call assert_equal(-1, utf16idx('', 1, v:true))
+
+  " error cases
+  call assert_equal(0, utf16idx("", 0))
+  call assert_equal(-1, utf16idx("", 1))
+  call assert_equal(-1, utf16idx("abc", -1))
+  call assert_equal(0, utf16idx(test_null_string(), 0))
+  call assert_equal(-1, utf16idx(test_null_string(), 1))
+  call assert_fails('let l = utf16idx([], 0)', 'E1174:')
+  call assert_fails('let l = utf16idx("ab", [])', 'E1210:')
+  call assert_fails('let l = utf16idx("ab", 0, [])', 'E1212:')
+endfunc
+
+" Test for utf16idx() using a character index
+func Test_utf16idx_from_charidx()
+  let str = "abc"
+  for i in str->strcharlen()->range()
+    call assert_equal(i, utf16idx(str, i, v:false, v:true))
+  endfor
+  call assert_equal(3, utf16idx(str, 3, v:false, v:true))
+  call assert_equal(-1, utf16idx(str, 4, v:false, v:true))
+
+  " UTF-16 index of a string with two byte characters
+  let str = "a©©b"
+  for i in str->strcharlen()->range()
+    call assert_equal(i, utf16idx(str, i, v:false, v:true))
+  endfor
+  call assert_equal(4, utf16idx(str, 4, v:false, v:true))
+  call assert_equal(-1, utf16idx(str, 5, v:false, v:true))
+
+  " UTF-16 index of a string with four byte characters
+  let str = "a😊😊b"
+  call assert_equal(0, utf16idx(str, 0, v:false, v:true))
+  call assert_equal(1, utf16idx(str, 1, v:false, v:true))
+  call assert_equal(3, utf16idx(str, 2, v:false, v:true))
+  call assert_equal(5, utf16idx(str, 3, v:false, v:true))
+  call assert_equal(6, utf16idx(str, 4, v:false, v:true))
+  call assert_equal(-1, utf16idx(str, 5, v:false, v:true))
+
+  " UTF-16 index of a string with composing characters
+  let str = '-á-b́'
+  for i in str->strcharlen()->range()
+    call assert_equal(i, utf16idx(str, i, v:false, v:true))
+  endfor
+  call assert_equal(4, utf16idx(str, 4, v:false, v:true))
+  call assert_equal(-1, utf16idx(str, 5, v:false, v:true))
+  for i in str->strchars()->range()
+    call assert_equal(i, utf16idx(str, i, v:true, v:true))
+  endfor
+  call assert_equal(6, utf16idx(str, 6, v:true, v:true))
+  call assert_equal(-1, utf16idx(str, 7, v:true, v:true))
+
+  " string with multiple composing characters
+  let str = '-ą́-ą́'
+  for i in str->strcharlen()->range()
+    call assert_equal(i, utf16idx(str, i, v:false, v:true))
+  endfor
+  call assert_equal(4, utf16idx(str, 4, v:false, v:true))
+  call assert_equal(-1, utf16idx(str, 5, v:false, v:true))
+  for i in str->strchars()->range()
+    call assert_equal(i, utf16idx(str, i, v:true, v:true))
+  endfor
+  call assert_equal(8, utf16idx(str, 8, v:true, v:true))
+  call assert_equal(-1, utf16idx(str, 9, v:true, v:true))
+
+  " empty string
+  call assert_equal(0, utf16idx('', 0, v:false, v:true))
+  call assert_equal(-1, utf16idx('', 1, v:false, v:true))
+  call assert_equal(0, utf16idx('', 0, v:true, v:true))
+  call assert_equal(-1, utf16idx('', 1, v:true, v:true))
+
+  " error cases
+  call assert_equal(0, utf16idx(test_null_string(), 0, v:true, v:true))
+  call assert_equal(-1, utf16idx(test_null_string(), 1, v:true, v:true))
+  call assert_fails('let l = utf16idx("ab", 0, v:false, [])', 'E1212:')
+endfunc
+
+" Test for strutf16len()
+func Test_strutf16len()
+  call assert_equal(3, strutf16len('abc'))
+  call assert_equal(3, 'abc'->strutf16len(v:true))
+  call assert_equal(4, strutf16len('a©©b'))
+  call assert_equal(4, strutf16len('a©©b', v:true))
+  call assert_equal(6, strutf16len('a😊😊b'))
+  call assert_equal(6, strutf16len('a😊😊b', v:true))
+  call assert_equal(4, strutf16len('-á-b́'))
+  call assert_equal(6, strutf16len('-á-b́', v:true))
+  call assert_equal(4, strutf16len('-ą́-ą́'))
+  call assert_equal(8, strutf16len('-ą́-ą́', v:true))
+  call assert_equal(0, strutf16len(''))
+
+  " error cases
+  call assert_fails('let l = strutf16len([])', 'E1174:')
+  call assert_fails('let l = strutf16len("a", [])', 'E1212:')
+  call assert_equal(0, strutf16len(test_null_string()))
+endfunc
+
+func Test_count()
+  let l = ['a', 'a', 'A', 'b']
+  call assert_equal(2, count(l, 'a'))
+  call assert_equal(1, count(l, 'A'))
+  call assert_equal(1, count(l, 'b'))
+  call assert_equal(0, count(l, 'B'))
+
+  call assert_equal(2, count(l, 'a', 0))
+  call assert_equal(1, count(l, 'A', 0))
+  call assert_equal(1, count(l, 'b', 0))
+  call assert_equal(0, count(l, 'B', 0))
+
+  call assert_equal(3, count(l, 'a', 1))
+  call assert_equal(3, count(l, 'A', 1))
+  call assert_equal(1, count(l, 'b', 1))
+  call assert_equal(1, count(l, 'B', 1))
+  call assert_equal(0, count(l, 'c', 1))
+
+  call assert_equal(1, count(l, 'a', 0, 1))
+  call assert_equal(2, count(l, 'a', 1, 1))
+  call assert_fails('call count(l, "a", 0, 10)', 'E684:')
+  call assert_fails('call count(l, "a", [])', 'E745:')
+
+  let d = {1: 'a', 2: 'a', 3: 'A', 4: 'b'}
+  call assert_equal(2, count(d, 'a'))
+  call assert_equal(1, count(d, 'A'))
+  call assert_equal(1, count(d, 'b'))
+  call assert_equal(0, count(d, 'B'))
+
+  call assert_equal(2, count(d, 'a', 0))
+  call assert_equal(1, count(d, 'A', 0))
+  call assert_equal(1, count(d, 'b', 0))
+  call assert_equal(0, count(d, 'B', 0))
+
+  call assert_equal(3, count(d, 'a', 1))
+  call assert_equal(3, count(d, 'A', 1))
+  call assert_equal(1, count(d, 'b', 1))
+  call assert_equal(1, count(d, 'B', 1))
+  call assert_equal(0, count(d, 'c', 1))
+
+  call assert_fails('call count(d, "a", 0, 1)', 'E474:')
+
+  call assert_equal(0, count("foo", "bar"))
+  call assert_equal(1, count("foo", "oo"))
+  call assert_equal(2, count("foo", "o"))
+  call assert_equal(0, count("foo", "O"))
+  call assert_equal(2, count("foo", "O", 1))
+  call assert_equal(2, count("fooooo", "oo"))
+  call assert_equal(0, count("foo", ""))
+
+  call assert_fails('call count(0, 0)', 'E712:')
+endfunc
+
+func Test_changenr()
+  new Xchangenr
+  call assert_equal(0, changenr())
+  norm ifoo
+  call assert_equal(1, changenr())
+  set undolevels=10
+  norm Sbar
+  call assert_equal(2, changenr())
+  undo
+  call assert_equal(1, changenr())
+  redo
+  call assert_equal(2, changenr())
+  bw!
+  set undolevels&
+endfunc
+
+func Test_filewritable()
+  new Xfilewritable
+  write!
+  call assert_equal(1, filewritable('Xfilewritable'))
+
+  call assert_notequal(0, setfperm('Xfilewritable', 'r--r-----'))
+  call assert_equal(0, filewritable('Xfilewritable'))
+
+  call assert_notequal(0, setfperm('Xfilewritable', 'rw-r-----'))
+  call assert_equal(1, 'Xfilewritable'->filewritable())
+
+  call assert_equal(0, filewritable('doesnotexist'))
+
+  call mkdir('Xwritedir', 'D')
+  call assert_equal(2, filewritable('Xwritedir'))
+
+  call delete('Xfilewritable')
+  bw!
+endfunc
+
+func Test_Executable()
+  if has('win32')
+    call assert_equal(1, executable('notepad'))
+    call assert_equal(1, 'notepad.exe'->executable())
+    call assert_equal(0, executable('notepad.exe.exe'))
+    call assert_equal(0, executable('shell32.dll'))
+    call assert_equal(0, executable('win.ini'))
+
+    " get "notepad" path and remove the leading drive and sep. (ex. 'C:\')
+    let notepadcmd = exepath('notepad.exe')
+    let driveroot = notepadcmd[:2]
+    let notepadcmd = notepadcmd[3:]
+    new
+    " check that the relative path works in /
+    execute 'lcd' driveroot
+    call assert_equal(1, executable(notepadcmd))
+    call assert_equal(driveroot .. notepadcmd, notepadcmd->exepath())
+    bwipe
+
+    " create "notepad.bat"
+    call mkdir('Xnotedir')
+    let notepadbat = fnamemodify('Xnotedir/notepad.bat', ':p')
+    call writefile([], notepadbat)
+    new
+    " check that the path and the pathext order is valid
+    lcd Xnotedir
+    let [pathext, $PATHEXT] = [$PATHEXT, '.com;.exe;.bat;.cmd']
+    call assert_equal(notepadbat, exepath('notepad'))
+    let $PATHEXT = pathext
+    bwipe
+    eval 'Xnotedir'->delete('rf')
+  elseif has('unix')
+    call assert_equal(1, 'cat'->executable())
+    call assert_equal(0, executable('nodogshere'))
+
+    " get "cat" path and remove the leading /
+    let catcmd = exepath('cat')[1:]
+    new
+    " check that the relative path works in /
+    lcd /
+    call assert_equal(1, executable(catcmd))
+    let result = catcmd->exepath()
+    " when using chroot looking for sbin/cat can return bin/cat, that is OK
+    if catcmd =~ '\<sbin\>' && result =~ '\<bin\>'
+      call assert_equal('/' .. substitute(catcmd, '\<sbin\>', 'bin', ''), result)
+    else
+      " /bin/cat and /usr/bin/cat may be hard linked, we could get either
+      let result = substitute(result, '/usr/bin/cat', '/bin/cat', '')
+      let catcmd = substitute(catcmd, 'usr/bin/cat', 'bin/cat', '')
+      call assert_equal('/' .. catcmd, result)
+    endif
+    bwipe
+  else
+    throw 'Skipped: does not work on this platform'
+  endif
+endfunc
+
+func Test_executable_windows_store_apps()
+  CheckMSWindows
+
+  " Windows Store apps install some 'decoy' .exe that require some careful
+  " handling as they behave similarly to symlinks.
+  let app_dir = expand("$LOCALAPPDATA\\Microsoft\\WindowsApps")
+  if !isdirectory(app_dir)
+    return
+  endif
+
+  let save_path = $PATH
+  let $PATH = app_dir
+  " Ensure executable() finds all the app .exes
+  for entry in readdir(app_dir)
+    if entry =~ '\.exe$'
+      call assert_true(executable(entry))
+    endif
+  endfor
+
+  let $PATH = save_path
+endfunc
+
+func Test_executable_longname()
+  CheckMSWindows
+
+  " Create a temporary .bat file with 205 characters in the name.
+  " Maximum length of a filename (including the path) on MS-Windows is 259
+  " characters.
+  " See https://docs.microsoft.com/en-us/windows/win32/fileio/maximum-file-path-limitation
+  let len = 259 - getcwd()->len() - 6
+  if len > 200
+    let len = 200
+  endif
+
+  let fname = 'X' . repeat('あ', len) . '.bat'
+  call writefile([], fname)
+  call assert_equal(1, executable(fname))
+  call delete(fname)
+endfunc
+
+func Test_hostname()
+  let hostname_vim = hostname()
+  if has('unix')
+    let hostname_system = systemlist('uname -n')[0]
+    call assert_equal(hostname_vim, hostname_system)
+  endif
+endfunc
+
+func Test_getpid()
+  " getpid() always returns the same value within a vim instance.
+  call assert_equal(getpid(), getpid())
+  if has('unix')
+    call assert_equal(systemlist('echo $PPID')[0], string(getpid()))
+  endif
+endfunc
+
+func Test_hlexists()
+  call assert_equal(0, hlexists('does_not_exist'))
+  call assert_equal(0, 'Number'->hlexists())
+  call assert_equal(0, highlight_exists('does_not_exist'))
+  call assert_equal(0, highlight_exists('Number'))
+  syntax on
+  call assert_equal(0, hlexists('does_not_exist'))
+  call assert_equal(1, hlexists('Number'))
+  call assert_equal(0, highlight_exists('does_not_exist'))
+  call assert_equal(1, highlight_exists('Number'))
+  syntax off
+endfunc
+
+" Test for the col() function
+func Test_col()
+  new
+  call setline(1, 'abcdef')
+  norm gg4|mx6|mY2|
+  call assert_equal(2, col('.'))
+  call assert_equal(7, col('$'))
+  call assert_equal(2, col('v'))
+  call assert_equal(4, col("'x"))
+  call assert_equal(6, col("'Y"))
+  call assert_equal(2, [1, 2]->col())
+  call assert_equal(7, col([1, '$']))
+
+  call assert_equal(0, col(''))
+  call assert_equal(0, col('x'))
+  call assert_equal(0, col([2, '$']))
+  call assert_equal(0, col([1, 100]))
+  call assert_equal(0, col([1]))
+  call assert_equal(0, col(test_null_list()))
+  call assert_fails('let c = col({})', 'E1222:')
+  call assert_fails('let c = col(".", [])', 'E1210:')
+
+  " test for getting the visual start column
+  func T()
+    let g:Vcol = col('v')
+    return ''
+  endfunc
+  let g:Vcol = 0
+  xmap <expr> <F2> T()
+  exe "normal gg3|ve\<F2>"
+  call assert_equal(3, g:Vcol)
+  xunmap <F2>
+  delfunc T
+
+  " Test for the visual line start and end marks '< and '>
+  call setline(1, ['one', 'one two', 'one two three'])
+  "normal! ggVG
+  call feedkeys("ggVG\<Esc>", 'xt')
+  call assert_equal(1, col("'<"))
+  call assert_equal(14, col("'>"))
+  " Delete the last line of the visually selected region
+  $d
+  call assert_notequal(14, col("'>"))
+
+  " Test with 'virtualedit'
+  set virtualedit=all
+  call cursor(1, 10)
+  call assert_equal(4, col('.'))
+  set virtualedit&
+
+  " Test for getting the column number in another window
+  let winid = win_getid()
+  new
+  call win_execute(winid, 'normal 1G$')
+  call assert_equal(3, col('.', winid))
+  call win_execute(winid, 'normal 2G')
+  call assert_equal(8, col('$', winid))
+  call assert_equal(0, col('.', 5001))
+
+  bw!
+endfunc
+
+" Test for input()
+func Test_input_func()
+  " Test for prompt with multiple lines
+  redir => v
+  call feedkeys(":let c = input(\"A\\nB\\nC\\n? \")\<CR>B\<CR>", 'xt')
+  redir END
+  call assert_equal("B", c)
+  call assert_equal(['A', 'B', 'C'], split(v, "\n"))
+
+  " Test for default value
+  call feedkeys(":let c = input('color? ', 'red')\<CR>\<CR>", 'xt')
+  call assert_equal('red', c)
+
+  " Test for completion at the input prompt
+  func! Tcomplete(arglead, cmdline, pos)
+    return "item1\nitem2\nitem3"
+  endfunc
+  call feedkeys(":let c = input('Q? ', '', 'custom,Tcomplete')\<CR>"
+        \ .. "\<C-A>\<CR>", 'xt')
+  delfunc Tcomplete
+  call assert_equal('item1 item2 item3', c)
+
+  " Test for using special characters as default input
+  call feedkeys(":let c = input('name? ', \"x\\<BS>y\")\<CR>\<CR>", 'xt')
+  call assert_equal('y', c)
+
+  " Test for using text with composing characters as default input
+  call feedkeys(":let c = input('name? ', \"ã̳\")\<CR>\<CR>", 'xt')
+  call assert_equal('ã̳', c)
+
+  " Test for using <CR> as default input
+  call feedkeys(":let c = input('name? ', \"\\<CR>\")\<CR>x\<CR>", 'xt')
+  call assert_equal(' x', c)
+
+  call assert_fails("call input('F:', '', 'invalid')", 'E180:')
+  call assert_fails("call input('F:', '', [])", 'E730:')
+endfunc
+
+" Test for the inputdialog() function
+func Test_inputdialog()
+  set timeout timeoutlen=10
+  if has('gui_running')
+    call assert_fails('let v=inputdialog([], "xx")', 'E730:')
+    call assert_fails('let v=inputdialog("Q", [])', 'E730:')
+  else
+    call feedkeys(":let v=inputdialog('Q:', 'xx', 'yy')\<CR>\<CR>", 'xt')
+    call assert_equal('xx', v)
+    call feedkeys(":let v=inputdialog('Q:', 'xx', 'yy')\<CR>\<Esc>", 'xt')
+    call assert_equal('yy', v)
+  endif
+  set timeout& timeoutlen&
+endfunc
+
+" Test for inputlist()
+func Test_inputlist()
+  call feedkeys(":let c = inputlist(['Select color:', '1. red', '2. green', '3. blue'])\<cr>1\<cr>", 'tx')
+  call assert_equal(1, c)
+  call feedkeys(":let c = ['Select color:', '1. red', '2. green', '3. blue']->inputlist()\<cr>2\<cr>", 'tx')
+  call assert_equal(2, c)
+  call feedkeys(":let c = inputlist(['Select color:', '1. red', '2. green', '3. blue'])\<cr>3\<cr>", 'tx')
+  call assert_equal(3, c)
+
+  " CR to cancel
+  call feedkeys(":let c = inputlist(['Select color:', '1. red', '2. green', '3. blue'])\<cr>\<cr>", 'tx')
+  call assert_equal(0, c)
+
+  " Esc to cancel
+  call feedkeys(":let c = inputlist(['Select color:', '1. red', '2. green', '3. blue'])\<cr>\<Esc>", 'tx')
+  call assert_equal(0, c)
+
+  " q to cancel
+  call feedkeys(":let c = inputlist(['Select color:', '1. red', '2. green', '3. blue'])\<cr>q", 'tx')
+  call assert_equal(0, c)
+
+  " Cancel after inputting a number
+  call feedkeys(":let c = inputlist(['Select color:', '1. red', '2. green', '3. blue'])\<cr>5q", 'tx')
+  call assert_equal(0, c)
+
+  " Use backspace to delete characters in the prompt
+  call feedkeys(":let c = inputlist(['Select color:', '1. red', '2. green', '3. blue'])\<cr>1\<BS>3\<BS>2\<cr>", 'tx')
+  call assert_equal(2, c)
+
+  " Use mouse to make a selection
+  call test_setmouse(&lines - 3, 2)
+  call feedkeys(":let c = inputlist(['Select color:', '1. red', '2. green', '3. blue'])\<cr>\<LeftMouse>", 'tx')
+  call assert_equal(1, c)
+  " Mouse click outside of the list
+  call test_setmouse(&lines - 6, 2)
+  call feedkeys(":let c = inputlist(['Select color:', '1. red', '2. green', '3. blue'])\<cr>\<LeftMouse>", 'tx')
+  call assert_equal(-2, c)
+
+  call assert_fails('call inputlist("")', 'E686:')
+  call assert_fails('call inputlist(test_null_list())', 'E686:')
+endfunc
+
+func Test_range_inputlist()
+  " flush out any garbage left in the buffer
+  while getchar(0)
+  endwhile
+
+  call feedkeys(":let result = inputlist(range(10))\<CR>1\<CR>", 'x')
+  call assert_equal(1, result)
+  call feedkeys(":let result = inputlist(range(3, 10))\<CR>1\<CR>", 'x')
+  call assert_equal(1, result)
+
+  unlet result
+endfunc
+
+func Test_balloon_show()
+  CheckFeature balloon_eval
+
+  " This won't do anything but must not crash either.
+  call balloon_show('hi!')
+  if !has('gui_running')
+    call balloon_show(range(3))
+    call balloon_show([])
+  endif
+endfunc
+
+func Test_setbufvar_options()
+  " This tests that aucmd_prepbuf() and aucmd_restbuf() properly restore the
+  " window layout and cursor position.
+  call assert_equal(1, winnr('$'))
+  split dummy_preview
+  resize 2
+  set winfixheight winfixwidth
+  let prev_id = win_getid()
+
+  wincmd j
+  let wh = winheight(0)
+  let dummy_buf = bufnr('dummy_buf1', v:true)
+  call setbufvar(dummy_buf, '&buftype', 'nofile')
+  execute 'belowright vertical split #' . dummy_buf
+  call assert_equal(wh, winheight(0))
+  let dum1_id = win_getid()
+  call setline(1, 'foo')
+  normal! V$
+  call assert_equal(4, col('.'))
+  call setbufvar('dummy_preview', '&buftype', 'nofile')
+  call assert_equal(4, col('.'))
+
+  wincmd h
+  let wh = winheight(0)
+  call setline(1, 'foo')
+  normal! V$
+  call assert_equal(4, col('.'))
+  let dummy_buf = bufnr('dummy_buf2', v:true)
+  eval 'nofile'->setbufvar(dummy_buf, '&buftype')
+  call assert_equal(4, col('.'))
+  execute 'belowright vertical split #' . dummy_buf
+  call assert_equal(wh, winheight(0))
+
+  bwipe!
+  call win_gotoid(prev_id)
+  bwipe!
+  call win_gotoid(dum1_id)
+  bwipe!
+endfunc
+
+func Test_setbufvar_keep_window_title()
+  CheckRunVimInTerminal
+  if !has('title') || empty(&t_ts)
+    throw "Skipped: can't get/set title"
+  endif
+
+  let lines =<< trim END
+      set title
+      edit Xa.txt
+      let g:buf = bufadd('Xb.txt')
+      inoremap <F2> <C-R>=setbufvar(g:buf, '&autoindent', 1) ?? ''<CR>
+  END
+  call writefile(lines, 'Xsetbufvar', 'D')
+  let buf = RunVimInTerminal('-S Xsetbufvar', {})
+  call WaitForAssert({-> assert_match('Xa.txt', term_gettitle(buf))}, 1000)
+
+  call term_sendkeys(buf, "i\<F2>")
+  call TermWait(buf)
+  call term_sendkeys(buf, "\<Esc>")
+  call TermWait(buf)
+  call assert_match('Xa.txt', term_gettitle(buf))
+
+  call StopVimInTerminal(buf)
+endfunc
+
+func Test_redo_in_nested_functions()
+  nnoremap g. :set opfunc=Operator<CR>g@
+  function Operator( type, ... )
+     let @x = 'XXX'
+     execute 'normal! g`[' . (a:type ==# 'line' ? 'V' : 'v') . 'g`]' . '"xp'
+  endfunction
+
+  function! Apply()
+      5,6normal! .
+  endfunction
+
+  new
+  call setline(1, repeat(['some "quoted" text', 'more "quoted" text'], 3))
+  1normal g.i"
+  call assert_equal('some "XXX" text', getline(1))
+  3,4normal .
+  call assert_equal('some "XXX" text', getline(3))
+  call assert_equal('more "XXX" text', getline(4))
+  call Apply()
+  call assert_equal('some "XXX" text', getline(5))
+  call assert_equal('more "XXX" text', getline(6))
+  bwipe!
+
+  nunmap g.
+  delfunc Operator
+  delfunc Apply
+endfunc
+
+func Test_trim()
+  call assert_equal("Testing", trim("  \t\r\r\x0BTesting  \t\n\r\n\t\x0B\x0B"))
+  call assert_equal("Testing", "  \t  \r\r\n\n\x0BTesting  \t\n\r\n\t\x0B\x0B"->trim())
+  call assert_equal("RESERVE", trim("xyz \twwRESERVEzyww \t\t", " wxyz\t"))
+  call assert_equal("wRE    \tSERVEzyww", trim("wRE    \tSERVEzyww"))
+  call assert_equal("abcd\t     xxxx   tail", trim(" \tabcd\t     xxxx   tail"))
+  call assert_equal("\tabcd\t     xxxx   tail", trim(" \tabcd\t     xxxx   tail", " "))
+  call assert_equal(" \tabcd\t     xxxx   tail", trim(" \tabcd\t     xxxx   tail", "abx"))
+  call assert_equal("RESERVE", trim("你RESERVE好", "你好"))
+  call assert_equal("您R E SER V E早", trim("你好您R E SER V E早好你你", "你好"))
+  call assert_equal("你好您R E SER V E早好你你", trim(" \n\r\r   你好您R E SER V E早好你你    \t  \x0B", ))
+  call assert_equal("您R E SER V E早好你你    \t  \x0B", trim("    你好您R E SER V E早好你你    \t  \x0B", " 你好"))
+  call assert_equal("您R E SER V E早好你你    \t  \x0B", trim("    tteesstttt你好您R E SER V E早好你你    \t  \x0B ttestt", " 你好tes"))
+  call assert_equal("您R E SER V E早好你你    \t  \x0B", trim("    tteesstttt你好您R E SER V E早好你你    \t  \x0B ttestt", "   你你你好好好tttsses"))
+  call assert_equal("留下", trim("这些些不要这些留下这些", "这些不要"))
+  call assert_equal("", trim("", ""))
+  call assert_equal("a", trim("a", ""))
+  call assert_equal("", trim("", "a"))
+
+  call assert_equal("vim", trim("  vim  ", " ", 0))
+  call assert_equal("vim  ", trim("  vim  ", " ", 1))
+  call assert_equal("  vim", trim("  vim  ", " ", 2))
+  call assert_fails('eval trim("  vim  ", " ", [])', 'E745:')
+  call assert_fails('eval trim("  vim  ", " ", -1)', 'E475:')
+  call assert_fails('eval trim("  vim  ", " ", 3)', 'E475:')
+  call assert_fails('eval trim("  vim  ", 0)', 'E1174:')
+
+  let chars = join(map(range(1, 0x20) + [0xa0], {n -> n->nr2char()}), '')
+  call assert_equal("x", trim(chars . "x" . chars))
+
+  call assert_fails('let c=trim([])', 'E730:')
+endfunc
+
+" Test for reg_recording() and reg_executing()
+func Test_reg_executing_and_recording()
+  let s:reg_stat = ''
+  func s:save_reg_stat()
+    let s:reg_stat = reg_recording() . ':' . reg_executing()
+    return ''
+  endfunc
+
+  new
+  call s:save_reg_stat()
+  call assert_equal(':', s:reg_stat)
+  call feedkeys("qa\"=s:save_reg_stat()\<CR>pq", 'xt')
+  call assert_equal('a:', s:reg_stat)
+  call feedkeys("@a", 'xt')
+  call assert_equal(':a', s:reg_stat)
+  call feedkeys("qb@aq", 'xt')
+  call assert_equal('b:a', s:reg_stat)
+  call feedkeys("q\"\"=s:save_reg_stat()\<CR>pq", 'xt')
+  call assert_equal('":', s:reg_stat)
+
+  " :normal command saves and restores reg_executing
+  let s:reg_stat = ''
+  let @q = ":call TestFunc()\<CR>:call s:save_reg_stat()\<CR>"
+  func TestFunc() abort
+    normal! ia
+  endfunc
+  call feedkeys("@q", 'xt')
+  call assert_equal(':q', s:reg_stat)
+  delfunc TestFunc
+
+  " getchar() command saves and restores reg_executing
+  map W :call TestFunc()<CR>
+  let @q = "W"
+  let g:typed = ''
+  let g:regs = []
+  func TestFunc() abort
+    let g:regs += [reg_executing()]
+    let g:typed = getchar(0)
+    let g:regs += [reg_executing()]
+  endfunc
+  call feedkeys("@qy", 'xt')
+  call assert_equal(char2nr("y"), g:typed)
+  call assert_equal(['q', 'q'], g:regs)
+  delfunc TestFunc
+  unmap W
+  unlet g:typed
+  unlet g:regs
+
+  " input() command saves and restores reg_executing
+  map W :call TestFunc()<CR>
+  let @q = "W"
+  let g:typed = ''
+  let g:regs = []
+  func TestFunc() abort
+    let g:regs += [reg_executing()]
+    let g:typed = '?'->input()
+    let g:regs += [reg_executing()]
+  endfunc
+  call feedkeys("@qy\<CR>", 'xt')
+  call assert_equal("y", g:typed)
+  call assert_equal(['q', 'q'], g:regs)
+  delfunc TestFunc
+  unmap W
+  unlet g:typed
+  unlet g:regs
+
+  bwipe!
+  delfunc s:save_reg_stat
+  unlet s:reg_stat
+endfunc
+
+func Test_inputsecret()
+  map W :call TestFunc()<CR>
+  let @q = "W"
+  let g:typed1 = ''
+  let g:typed2 = ''
+  let g:regs = []
+  func TestFunc() abort
+    let g:typed1 = '?'->inputsecret()
+    let g:typed2 = inputsecret('password: ')
+  endfunc
+  call feedkeys("@qsomething\<CR>else\<CR>", 'xt')
+  call assert_equal("something", g:typed1)
+  call assert_equal("else", g:typed2)
+  delfunc TestFunc
+  unmap W
+  unlet g:typed1
+  unlet g:typed2
+endfunc
+
+func Test_getchar()
+  call feedkeys('a', '')
+  call assert_equal(char2nr('a'), getchar())
+  call assert_equal(0, getchar(0))
+  call assert_equal(0, getchar(1))
+
+  call feedkeys('a', '')
+  call assert_equal('a', getcharstr())
+  call assert_equal('', getcharstr(0))
+  call assert_equal('', getcharstr(1))
+
+  call feedkeys("\<M-F2>", '')
+  call assert_equal("\<M-F2>", getchar(0))
+  call assert_equal(0, getchar(0))
+
+  call setline(1, 'xxxx')
+  call test_setmouse(1, 3)
+  let v:mouse_win = 9
+  let v:mouse_winid = 9
+  let v:mouse_lnum = 9
+  let v:mouse_col = 9
+  call feedkeys("\<S-LeftMouse>", '')
+  call assert_equal("\<S-LeftMouse>", getchar())
+  call assert_equal(1, v:mouse_win)
+  call assert_equal(win_getid(1), v:mouse_winid)
+  call assert_equal(1, v:mouse_lnum)
+  call assert_equal(3, v:mouse_col)
+  enew!
+endfunc
+
+func Test_libcall_libcallnr()
+  CheckFeature libcall
+
+  if has('win32')
+    let libc = 'msvcrt.dll'
+  elseif has('mac')
+    let libc = 'libSystem.B.dylib'
+  elseif executable('ldd')
+    let libc = matchstr(split(system('ldd ' . GetVimProg())), '/libc\.so\>')
+  endif
+  if get(l:, 'libc', '') ==# ''
+    " On Unix, libc.so can be in various places.
+    if has('linux')
+      " There is not documented but regarding the 1st argument of glibc's
+      " dlopen an empty string and nullptr are equivalent, so using an empty
+      " string for the 1st argument of libcall allows to call functions.
+      let libc = ''
+    elseif has('sun')
+      " Set the path to libc.so according to the architecture.
+      let test_bits = system('file ' . GetVimProg())
+      let test_arch = system('uname -p')
+      if test_bits =~ '64-bit' && test_arch =~ 'sparc'
+        let libc = '/usr/lib/sparcv9/libc.so'
+      elseif test_bits =~ '64-bit' && test_arch =~ 'i386'
+        let libc = '/usr/lib/amd64/libc.so'
+      else
+        let libc = '/usr/lib/libc.so'
+      endif
+    else
+      " Unfortunately skip this test until a good way is found.
+      return
+    endif
+  endif
+
+  if has('win32')
+    call assert_equal($USERPROFILE, 'USERPROFILE'->libcall(libc, 'getenv'))
+  else
+    call assert_equal($HOME, 'HOME'->libcall(libc, 'getenv'))
+  endif
+
+  " If function returns NULL, libcall() should return an empty string.
+  call assert_equal('', libcall(libc, 'getenv', 'X_ENV_DOES_NOT_EXIT'))
+
+  " Test libcallnr() with string and integer argument.
+  call assert_equal(4, 'abcd'->libcallnr(libc, 'strlen'))
+  call assert_equal(char2nr('A'), char2nr('a')->libcallnr(libc, 'toupper'))
+
+  call assert_fails("call libcall(libc, 'Xdoesnotexist_', '')", ['', 'E364:'])
+  call assert_fails("call libcallnr(libc, 'Xdoesnotexist_', '')", ['', 'E364:'])
+
+  call assert_fails("call libcall('Xdoesnotexist_', 'getenv', 'HOME')", ['', 'E364:'])
+  call assert_fails("call libcallnr('Xdoesnotexist_', 'strlen', 'abcd')", ['', 'E364:'])
+endfunc
+
+sandbox function Fsandbox()
+  normal ix
+endfunc
+
+func Test_func_sandbox()
+  sandbox let F = {-> 'hello'}
+  call assert_equal('hello', F())
+
+  sandbox let F = {-> "normal ix\<Esc>"->execute()}
+  call assert_fails('call F()', 'E48:')
+  unlet F
+
+  call assert_fails('call Fsandbox()', 'E48:')
+  delfunc Fsandbox
+
+  " From a sandbox try to set a predefined variable (which cannot be modified
+  " from a sandbox)
+  call assert_fails('sandbox let v:lnum = 10', 'E794:')
+endfunc
+
+func EditAnotherFile()
+  let word = expand('<cword>')
+  edit Xfuncrange2
+endfunc
+
+func Test_func_range_with_edit()
+  " Define a function that edits another buffer, then call it with a range that
+  " is invalid in that buffer.
+  call writefile(['just one line'], 'Xfuncrange2', 'D')
+  new
+  eval 10->range()->setline(1)
+  write Xfuncrange1
+  call assert_fails('5,8call EditAnotherFile()', 'E16:')
+
+  call delete('Xfuncrange1')
+  bwipe!
+endfunc
+
+func Test_func_exists_on_reload()
+  call writefile(['func ExistingFunction()', 'echo "yes"', 'endfunc'], 'Xfuncexists', 'D')
+  call assert_equal(0, exists('*ExistingFunction'))
+  source Xfuncexists
+  call assert_equal(1, '*ExistingFunction'->exists())
+  " Redefining a function when reloading a script is OK.
+  source Xfuncexists
+  call assert_equal(1, exists('*ExistingFunction'))
+
+  " But redefining in another script is not OK.
+  call writefile(['func ExistingFunction()', 'echo "yes"', 'endfunc'], 'Xfuncexists2', 'D')
+  call assert_fails('source Xfuncexists2', 'E122:')
+
+  " Defining a new function from the cmdline should fail if the function is
+  " already defined
+  call assert_fails('call feedkeys(":func ExistingFunction()\<CR>", "xt")', 'E122:')
+
+  delfunc ExistingFunction
+  call assert_equal(0, exists('*ExistingFunction'))
+  call writefile([
+	\ 'func ExistingFunction()', 'echo "yes"', 'endfunc',
+	\ 'func ExistingFunction()', 'echo "no"', 'endfunc',
+	\ ], 'Xfuncexists')
+  call assert_fails('source Xfuncexists', 'E122:')
+  call assert_equal(1, exists('*ExistingFunction'))
+
+  delfunc ExistingFunction
+endfunc
+
+" Test confirm({msg} [, {choices} [, {default} [, {type}]]])
+func Test_confirm()
+  CheckUnix
+  CheckNotGui
+
+  call feedkeys('o', 'L')
+  let a = confirm('Press O to proceed')
+  call assert_equal(1, a)
+
+  call feedkeys('y', 'L')
+  let a = 'Are you sure?'->confirm("&Yes\n&No")
+  call assert_equal(1, a)
+
+  call feedkeys('n', 'L')
+  let a = confirm('Are you sure?', "&Yes\n&No")
+  call assert_equal(2, a)
+
+  " confirm() should return 0 when pressing CTRL-C.
+  call feedkeys("\<C-C>", 'L')
+  let a = confirm('Are you sure?', "&Yes\n&No")
+  call assert_equal(0, a)
+
+  " <Esc> requires another character to avoid it being seen as the start of an
+  " escape sequence.  Zero should be harmless.
+  eval "\<Esc>0"->feedkeys('L')
+  let a = confirm('Are you sure?', "&Yes\n&No")
+  call assert_equal(0, a)
+
+  " Default choice is returned when pressing <CR>.
+  call feedkeys("\<CR>", 'L')
+  let a = confirm('Are you sure?', "&Yes\n&No")
+  call assert_equal(1, a)
+
+  call feedkeys("\<CR>", 'L')
+  let a = confirm('Are you sure?', "&Yes\n&No", 2)
+  call assert_equal(2, a)
+
+  call feedkeys("\<CR>", 'L')
+  let a = confirm('Are you sure?', "&Yes\n&No", 0)
+  call assert_equal(0, a)
+
+  " Test with the {type} 4th argument
+  for type in ['Error', 'Question', 'Info', 'Warning', 'Generic']
+    call feedkeys('y', 'L')
+    let a = confirm('Are you sure?', "&Yes\n&No\n", 1, type)
+    call assert_equal(1, a)
+  endfor
+
+  call assert_fails('call confirm([])', 'E730:')
+  call assert_fails('call confirm("Are you sure?", [])', 'E730:')
+  call assert_fails('call confirm("Are you sure?", "&Yes\n&No\n", [])', 'E745:')
+  call assert_fails('call confirm("Are you sure?", "&Yes\n&No\n", 0, [])', 'E730:')
+endfunc
+
+func Test_platform_name()
+  " The system matches at most only one name.
+  let names = ['amiga', 'bsd', 'hpux', 'linux', 'mac', 'qnx', 'sun', 'vms', 'win32', 'win32unix']
+  call assert_inrange(0, 1, len(filter(copy(names), 'has(v:val)')))
+
+  " Is Unix?
+  call assert_equal(has('bsd'), has('bsd') && has('unix'))
+  call assert_equal(has('hpux'), has('hpux') && has('unix'))
+  call assert_equal(has('linux'), has('linux') && has('unix'))
+  call assert_equal(has('mac'), has('mac') && has('unix'))
+  call assert_equal(has('qnx'), has('qnx') && has('unix'))
+  call assert_equal(has('sun'), has('sun') && has('unix'))
+  call assert_equal(has('win32'), has('win32') && !has('unix'))
+  call assert_equal(has('win32unix'), has('win32unix') && has('unix'))
+
+  if has('unix') && executable('uname')
+    let uname = system('uname')
+    " GNU userland on BSD kernels (e.g., GNU/kFreeBSD) don't have BSD defined
+    call assert_equal(uname =~? '\%(GNU/k\w\+\)\@<!BSD\|DragonFly', has('bsd'))
+    call assert_equal(uname =~? 'HP-UX', has('hpux'))
+    call assert_equal(uname =~? 'Linux', has('linux'))
+    call assert_equal(uname =~? 'Darwin', has('mac'))
+    call assert_equal(uname =~? 'QNX', has('qnx'))
+    call assert_equal(uname =~? 'SunOS', has('sun'))
+    call assert_equal(uname =~? 'CYGWIN\|MSYS', has('win32unix'))
+  endif
+endfunc
+
+func Test_readdir()
+  call mkdir('Xreaddir', 'R')
+  call writefile([], 'Xreaddir/foo.txt')
+  call writefile([], 'Xreaddir/bar.txt')
+  call mkdir('Xreaddir/dir')
+
+  " All results
+  let files = readdir('Xreaddir')
+  call assert_equal(['bar.txt', 'dir', 'foo.txt'], sort(files))
+
+  " Only results containing "f"
+  let files = 'Xreaddir'->readdir({ x -> stridx(x, 'f') != -1 })
+  call assert_equal(['foo.txt'], sort(files))
+
+  " Only .txt files
+  let files = readdir('Xreaddir', { x -> x =~ '.txt$' })
+  call assert_equal(['bar.txt', 'foo.txt'], sort(files))
+
+  " Only .txt files with string
+  let files = readdir('Xreaddir', 'v:val =~ ".txt$"')
+  call assert_equal(['bar.txt', 'foo.txt'], sort(files))
+
+  " Limit to 1 result.
+  let l = []
+  let files = readdir('Xreaddir', {x -> len(add(l, x)) == 2 ? -1 : 1})
+  call assert_equal(1, len(files))
+
+  " Nested readdir() must not crash
+  let files = readdir('Xreaddir', 'readdir("Xreaddir", "1") != []')
+  call sort(files)->assert_equal(['bar.txt', 'dir', 'foo.txt'])
+endfunc
+
+func Test_readdirex()
+  call mkdir('Xexdir', 'R')
+  call writefile(['foo'], 'Xexdir/foo.txt')
+  call writefile(['barbar'], 'Xexdir/bar.txt')
+  call mkdir('Xexdir/dir')
+
+  " All results
+  let files = readdirex('Xexdir')->map({-> v:val.name})
+  call assert_equal(['bar.txt', 'dir', 'foo.txt'], sort(files))
+  let sizes = readdirex('Xexdir')->map({-> v:val.size})
+  call assert_equal([0, 4, 7], sort(sizes))
+
+  " Only results containing "f"
+  let files = 'Xexdir'->readdirex({ e -> stridx(e.name, 'f') != -1 })
+			  \ ->map({-> v:val.name})
+  call assert_equal(['foo.txt'], sort(files))
+
+  " Only .txt files
+  let files = readdirex('Xexdir', { e -> e.name =~ '.txt$' })
+			  \ ->map({-> v:val.name})
+  call assert_equal(['bar.txt', 'foo.txt'], sort(files))
+
+  " Only .txt files with string
+  let files = readdirex('Xexdir', 'v:val.name =~ ".txt$"')
+			  \ ->map({-> v:val.name})
+  call assert_equal(['bar.txt', 'foo.txt'], sort(files))
+
+  " Limit to 1 result.
+  let l = []
+  let files = readdirex('Xexdir', {e -> len(add(l, e.name)) == 2 ? -1 : 1})
+			  \ ->map({-> v:val.name})
+  call assert_equal(1, len(files))
+
+  " Nested readdirex() must not crash
+  let files = readdirex('Xexdir', 'readdirex("Xexdir", "1") != []')
+			  \ ->map({-> v:val.name})
+  call sort(files)->assert_equal(['bar.txt', 'dir', 'foo.txt'])
+
+  " report broken link correctly
+  if has("unix")
+    call writefile([], 'Xexdir/abc.txt')
+    call system("ln -s Xexdir/abc.txt Xexdir/link")
+    call delete('Xexdir/abc.txt')
+    let files = readdirex('Xexdir', 'readdirex("Xexdir", "1") != []')
+			  \ ->map({-> v:val.name .. '_' .. v:val.type})
+    call sort(files)->assert_equal(
+        \ ['bar.txt_file', 'dir_dir', 'foo.txt_file', 'link_link'])
+  endif
+
+  call assert_fails('call readdirex("doesnotexist")', 'E484:')
+endfunc
+
+func Test_readdirex_sort()
+  CheckUnix
+  " Skip tests on Mac OS X and Cygwin (does not allow several files with different casing)
+  if has("osxdarwin") || has("osx") || has("macunix") || has("win32unix")
+    throw 'Skipped: Test_readdirex_sort on systems that do not allow this using the default filesystem'
+  endif
+  let _collate = v:collate
+  call mkdir('Xsortdir2', 'R')
+  call writefile(['1'], 'Xsortdir2/README.txt')
+  call writefile(['2'], 'Xsortdir2/Readme.txt')
+  call writefile(['3'], 'Xsortdir2/readme.txt')
+
+  " 1) default
+  let files = readdirex('Xsortdir2')->map({-> v:val.name})
+  let default = copy(files)
+  call assert_equal(['README.txt', 'Readme.txt', 'readme.txt'], files, 'sort using default')
+
+  " 2) no sorting
+  let files = readdirex('Xsortdir2', 1, #{sort: 'none'})->map({-> v:val.name})
+  let unsorted = copy(files)
+  call assert_equal(['README.txt', 'Readme.txt', 'readme.txt'], sort(files), 'unsorted')
+  call assert_fails("call readdirex('Xsortdir2', 1, #{slort: 'none'})", 'E857: Dictionary key "sort" required')
+
+  " 3) sort by case (same as default)
+  let files = readdirex('Xsortdir2', 1, #{sort: 'case'})->map({-> v:val.name})
+  call assert_equal(default, files, 'sort by case')
+
+  " 4) sort by ignoring case
+  let files = readdirex('Xsortdir2', 1, #{sort: 'icase'})->map({-> v:val.name})
+  call assert_equal(unsorted->sort('i'), files, 'sort by icase')
+
+  " 5) Default Collation
+  let collate = v:collate
+  lang collate C
+  let files = readdirex('Xsortdir2', 1, #{sort: 'collate'})->map({-> v:val.name})
+  call assert_equal(['README.txt', 'Readme.txt', 'readme.txt'], files, 'sort by C collation')
+
+  " 6) Collation de_DE
+  " Switch locale, this may not work on the CI system, if the locale isn't
+  " available
+  try
+    lang collate de_DE
+    let files = readdirex('Xsortdir2', 1, #{sort: 'collate'})->map({-> v:val.name})
+    call assert_equal(['readme.txt', 'Readme.txt', 'README.txt'], files, 'sort by de_DE collation')
+  catch
+    throw 'Skipped: de_DE collation is not available'
+
+  finally
+    exe 'lang collate' collate
+  endtry
+endfunc
+
+func Test_readdir_sort()
+  " some more cases for testing sorting for readdirex
+  let dir = 'Xsortdir3'
+  call mkdir(dir, 'R')
+  call writefile(['1'], dir .. '/README.txt')
+  call writefile(['2'], dir .. '/Readm.txt')
+  call writefile(['3'], dir .. '/read.txt')
+  call writefile(['4'], dir .. '/Z.txt')
+  call writefile(['5'], dir .. '/a.txt')
+  call writefile(['6'], dir .. '/b.txt')
+
+  " 1) default
+  let files = readdir(dir)
+  let default = copy(files)
+  call assert_equal(default->sort(), files, 'sort using default')
+
+  " 2) sort by case (same as default)
+  let files = readdir(dir, '1', #{sort: 'case'})
+  call assert_equal(default, files, 'sort using default')
+
+  " 3) sort by ignoring case
+  let files = readdir(dir, '1', #{sort: 'icase'})
+  call assert_equal(default->sort('i'), files, 'sort by ignoring case')
+
+  " 4) collation
+  let collate = v:collate
+  lang collate C
+  let files = readdir(dir, 1, #{sort: 'collate'})
+  call assert_equal(default->sort(), files, 'sort by C collation')
+  exe "lang collate" collate
+
+  " 5) Errors
+  call assert_fails('call readdir(dir, 1, 1)', 'E1206:')
+  call assert_fails('call readdir(dir, 1, #{sorta: 1})')
+  call assert_fails('call readdir(dir, 1, test_null_dict())', 'E1297:')
+  call assert_fails('call readdirex(dir, 1, 1)', 'E1206:')
+  call assert_fails('call readdirex(dir, 1, #{sorta: 1})')
+  call assert_fails('call readdirex(dir, 1, test_null_dict())', 'E1297:')
+
+  " 6) ignore other values in dict
+  let files = readdir(dir, '1', #{sort: 'c'})
+  call assert_equal(default, files, 'sort using default2')
+
+  " Cleanup
+  exe "lang collate" collate
+endfunc
+
+func Test_delete_rf()
+  call mkdir('Xrfdir')
+  call writefile([], 'Xrfdir/foo.txt')
+  call writefile([], 'Xrfdir/bar.txt')
+  call mkdir('Xrfdir/[a-1]')  " issue #696
+  call writefile([], 'Xrfdir/[a-1]/foo.txt')
+  call writefile([], 'Xrfdir/[a-1]/bar.txt')
+  call assert_true(filereadable('Xrfdir/foo.txt'))
+  call assert_true('Xrfdir/[a-1]/foo.txt'->filereadable())
+
+  call assert_equal(0, delete('Xrfdir', 'rf'))
+  call assert_false(filereadable('Xrfdir/foo.txt'))
+  call assert_false(filereadable('Xrfdir/[a-1]/foo.txt'))
+
+  if has('unix')
+    call mkdir('Xrfdir/Xdir2', 'p')
+    silent !chmod 555 Xrfdir
+    call assert_equal(-1, delete('Xrfdir/Xdir2', 'rf'))
+    call assert_equal(-1, delete('Xrfdir', 'rf'))
+    silent !chmod 755 Xrfdir
+    call assert_equal(0, delete('Xrfdir', 'rf'))
+  endif
+endfunc
+
+func Test_call()
+  call assert_equal(3, call('len', [123]))
+  call assert_equal(3, 'len'->call([123]))
+  call assert_fails("call call('len', 123)", 'E1211:')
+  call assert_equal(0, call('', []))
+  call assert_equal(0, call('len', test_null_list()))
+
+  function Mylen() dict
+     return len(self.data)
+  endfunction
+  let mydict = {'data': [0, 1, 2, 3], 'len': function("Mylen")}
+  eval mydict.len->call([], mydict)->assert_equal(4)
+  call assert_fails("call call('Mylen', [], 0)", 'E1206:')
+  call assert_fails('call foo', 'E107:')
+
+  " These once caused a crash.
+  call call(test_null_function(), [])
+  call call(test_null_partial(), [])
+  call assert_fails('call test_null_function()()', 'E1192:')
+  call assert_fails('call test_null_partial()()', 'E117:')
+
+  let lines =<< trim END
+      let Time = 'localtime'
+      call Time()
+  END
+  call v9.CheckScriptFailure(lines, 'E1085:')
+endfunc
+
+func Test_char2nr()
+  call assert_equal(12354, char2nr('あ', 1))
+  call assert_equal(120, 'x'->char2nr())
+  set encoding=latin1
+  call assert_equal(120, 'x'->char2nr())
+  set encoding=utf-8
+endfunc
+
+func Test_charclass()
+  call assert_equal(0, charclass(' '))
+  call assert_equal(1, charclass('.'))
+  call assert_equal(2, charclass('x'))
+  call assert_equal(3, charclass("\u203c"))
+  " this used to crash vim
+  call assert_equal(0, "xxx"[-1]->charclass())
+endfunc
+
+func Test_eventhandler()
+  call assert_equal(0, eventhandler())
+endfunc
+
+func Test_bufadd_bufload()
+  call assert_equal(0, bufexists('someName'))
+  let buf = bufadd('someName')
+  call assert_notequal(0, buf)
+  call assert_equal(1, bufexists('someName'))
+  call assert_equal(0, getbufvar(buf, '&buflisted'))
+  call assert_equal(0, bufloaded(buf))
+  call bufload(buf)
+  call assert_equal(1, bufloaded(buf))
+  call assert_equal([''], getbufline(buf, 1, '$'))
+
+  let curbuf = bufnr('')
+  eval ['some', 'text']->writefile('XotherName')
+  let buf = 'XotherName'->bufadd()
+  call assert_notequal(0, buf)
+  eval 'XotherName'->bufexists()->assert_equal(1)
+  call assert_equal(0, getbufvar(buf, '&buflisted'))
+  call assert_equal(0, bufloaded(buf))
+  eval buf->bufload()
+  call assert_equal(1, bufloaded(buf))
+  call assert_equal(['some', 'text'], getbufline(buf, 1, '$'))
+  call assert_equal(curbuf, bufnr(''))
+
+  let buf1 = bufadd('')
+  let buf2 = bufadd('')
+  call assert_notequal(0, buf1)
+  call assert_notequal(0, buf2)
+  call assert_notequal(buf1, buf2)
+  call assert_equal(1, bufexists(buf1))
+  call assert_equal(1, bufexists(buf2))
+  call assert_equal(0, bufloaded(buf1))
+  exe 'bwipe ' .. buf1
+  call assert_equal(0, bufexists(buf1))
+  call assert_equal(1, bufexists(buf2))
+  exe 'bwipe ' .. buf2
+  call assert_equal(0, bufexists(buf2))
+
+  " When 'buftype' is "nofile" then bufload() does not read the file.
+  " Other values too.
+  for val in [['nofile', 0],
+            \ ['nowrite', 1],
+            \ ['acwrite', 1],
+            \ ['quickfix', 0],
+            \ ['help', 1],
+            \ ['terminal', 0],
+            \ ['prompt', 0],
+            \ ['popup', 0],
+            \ ]
+    bwipe! XotherName
+    let buf = bufadd('XotherName')
+    call setbufvar(buf, '&bt', val[0])
+    call bufload(buf)
+    call assert_equal(val[1] ? ['some', 'text'] : [''], getbufline(buf, 1, '$'), val[0])
+  endfor
+
+  bwipe someName
+  bwipe XotherName
+  call assert_equal(0, bufexists('someName'))
+  call delete('XotherName')
+endfunc
+
+func Test_state()
+  CheckRunVimInTerminal
+
+  let getstate = ":echo 'state: ' .. g:state .. '; mode: ' .. g:mode\<CR>"
+
+  let lines =<< trim END
+	call setline(1, ['one', 'two', 'three'])
+	map ;; gg
+	set complete=.
+	func RunTimer()
+	  call timer_start(10, {id -> execute('let g:state = state()') .. execute('let g:mode = mode()')})
+	endfunc
+	au Filetype foobar let g:state = state()|let g:mode = mode()
+  END
+  call writefile(lines, 'XState')
+  let buf = RunVimInTerminal('-S XState', #{rows: 6})
+
+  " Using a ":" command Vim is busy, thus "S" is returned
+  call term_sendkeys(buf, ":echo 'state: ' .. state() .. '; mode: ' .. mode()\<CR>")
+  call WaitForAssert({-> assert_match('state: S; mode: n', term_getline(buf, 6))}, 1000)
+  call term_sendkeys(buf, ":\<CR>")
+
+  " Using a timer callback
+  call term_sendkeys(buf, ":call RunTimer()\<CR>")
+  call TermWait(buf, 25)
+  call term_sendkeys(buf, getstate)
+  call WaitForAssert({-> assert_match('state: c; mode: n', term_getline(buf, 6))}, 1000)
+
+  " Halfway a mapping
+  call term_sendkeys(buf, ":call RunTimer()\<CR>;")
+  call TermWait(buf, 25)
+  call term_sendkeys(buf, ";")
+  call term_sendkeys(buf, getstate)
+  call WaitForAssert({-> assert_match('state: mSc; mode: n', term_getline(buf, 6))}, 1000)
+
+  " Insert mode completion (bit slower on Mac)
+  call term_sendkeys(buf, ":call RunTimer()\<CR>Got\<C-N>")
+  call TermWait(buf, 25)
+  call term_sendkeys(buf, "\<Esc>")
+  call term_sendkeys(buf, getstate)
+  call WaitForAssert({-> assert_match('state: aSc; mode: i', term_getline(buf, 6))}, 1000)
+
+  " Autocommand executing
+  call term_sendkeys(buf, ":set filetype=foobar\<CR>")
+  call TermWait(buf, 25)
+  call term_sendkeys(buf, getstate)
+  call WaitForAssert({-> assert_match('state: xS; mode: n', term_getline(buf, 6))}, 1000)
+
+  " Todo: "w" - waiting for ch_evalexpr()
+
+  " messages scrolled
+  call term_sendkeys(buf, ":call RunTimer()\<CR>:echo \"one\\ntwo\\nthree\"\<CR>")
+  call TermWait(buf, 25)
+  call term_sendkeys(buf, "\<CR>")
+  call term_sendkeys(buf, getstate)
+  call WaitForAssert({-> assert_match('state: Scs; mode: r', term_getline(buf, 6))}, 1000)
+
+  call StopVimInTerminal(buf)
+  call delete('XState')
+endfunc
+
+func Test_range()
+  " destructuring
+  let [x, y] = range(2)
+  call assert_equal([0, 1], [x, y])
+
+  " index
+  call assert_equal(4, range(1, 10)[3])
+
+  " add()
+  call assert_equal([0, 1, 2, 3], add(range(3), 3))
+  call assert_equal([0, 1, 2, [0, 1, 2]], add([0, 1, 2], range(3)))
+  call assert_equal([0, 1, 2, [0, 1, 2]], add(range(3), range(3)))
+
+  " append()
+  new
+  call append('.', range(5))
+  call assert_equal(['', '0', '1', '2', '3', '4'], getline(1, '$'))
+  bwipe!
+
+  " appendbufline()
+  new
+  call appendbufline(bufnr(''), '.', range(5))
+  call assert_equal(['0', '1', '2', '3', '4', ''], getline(1, '$'))
+  bwipe!
+
+  " call()
+  func TwoArgs(a, b)
+    return [a:a, a:b]
+  endfunc
+  call assert_equal([0, 1], call('TwoArgs', range(2)))
+
+  " col()
+  new
+  call setline(1, ['foo', 'bar'])
+  call assert_equal(2, col(range(1, 2)))
+  bwipe!
+
+  " complete()
+  execute "normal! a\<C-r>=[complete(col('.'), range(10)), ''][1]\<CR>"
+  " complete_info()
+  execute "normal! a\<C-r>=[complete(col('.'), range(10)), ''][1]\<CR>\<C-r>=[complete_info(range(5)), ''][1]\<CR>"
+
+  " copy()
+  call assert_equal([1, 2, 3], copy(range(1, 3)))
+
+  " count()
+  call assert_equal(0, count(range(0), 3))
+  call assert_equal(0, count(range(2), 3))
+  call assert_equal(1, count(range(5), 3))
+
+  " cursor()
+  new
+  call setline(1, ['aaa', 'bbb', 'ccc'])
+  call cursor(range(1, 2))
+  call assert_equal([2, 1], [col('.'), line('.')])
+  bwipe!
+
+  " deepcopy()
+  call assert_equal([1, 2, 3], deepcopy(range(1, 3)))
+
+  " empty()
+  call assert_true(empty(range(0)))
+  call assert_false(empty(range(2)))
+
+  " execute()
+  new
+  call setline(1, ['aaa', 'bbb', 'ccc'])
+  call execute(range(3))
+  call assert_equal(2, line('.'))
+  bwipe!
+
+  " extend()
+  call assert_equal([1, 2, 3, 4], extend([1], range(2, 4)))
+  call assert_equal([1, 2, 3, 4], extend(range(1, 1), range(2, 4)))
+  call assert_equal([1, 2, 3, 4], extend(range(1, 1), [2, 3, 4]))
+
+  " filter()
+  call assert_equal([1, 3], filter(range(5), 'v:val % 2'))
+  call assert_equal([1, 5, 7, 11, 13], filter(filter(range(15), 'v:val % 2'), 'v:val % 3'))
+
+  " funcref()
+  call assert_equal([0, 1], funcref('TwoArgs', range(2))())
+
+  " function()
+  call assert_equal([0, 1], function('TwoArgs', range(2))())
+
+  " garbagecollect()
+  let thelist = [1, range(2), 3]
+  let otherlist = range(3)
+  call test_garbagecollect_now()
+
+  " get()
+  call assert_equal(4, get(range(1, 10), 3))
+  call assert_equal(-1, get(range(1, 10), 42, -1))
+
+  " index()
+  call assert_equal(1, index(range(1, 5), 2))
+  call assert_fails("echo index([1, 2], 1, [])", 'E745:')
+
+  " insert()
+  call assert_equal([42, 1, 2, 3, 4, 5], insert(range(1, 5), 42))
+  call assert_equal([42, 1, 2, 3, 4, 5], insert(range(1, 5), 42, 0))
+  call assert_equal([1, 42, 2, 3, 4, 5], insert(range(1, 5), 42, 1))
+  call assert_equal([1, 2, 3, 4, 42, 5], insert(range(1, 5), 42, 4))
+  call assert_equal([1, 2, 3, 4, 42, 5], insert(range(1, 5), 42, -1))
+  call assert_equal([1, 2, 3, 4, 5, 42], insert(range(1, 5), 42, 5))
+
+  " join()
+  call assert_equal('0 1 2 3 4', join(range(5)))
+
+  " json_encode()
+  call assert_equal('[0,1,2,3]', json_encode(range(4)))
+
+  " len()
+  call assert_equal(0, len(range(0)))
+  call assert_equal(2, len(range(2)))
+  call assert_equal(5, len(range(0, 12, 3)))
+  call assert_equal(4, len(range(3, 0, -1)))
+
+  " list2str()
+  call assert_equal('ABC', list2str(range(65, 67)))
+  call assert_fails('let s = list2str(5)', 'E1211:')
+
+  " lock()
+  let thelist = range(5)
+  lockvar thelist
+
+  " map()
+  call assert_equal([0, 2, 4, 6, 8], map(range(5), 'v:val * 2'))
+  call assert_equal([3, 5, 7, 9, 11], map(map(range(5), 'v:val * 2'), 'v:val + 3'))
+  call assert_equal([2, 6], map(filter(range(5), 'v:val % 2'), 'v:val * 2'))
+  call assert_equal([2, 4, 8], filter(map(range(5), 'v:val * 2'), 'v:val % 3'))
+
+  " match()
+  call assert_equal(3, match(range(5), 3))
+
+  " matchaddpos()
+  highlight MyGreenGroup ctermbg=green guibg=green
+  call matchaddpos('MyGreenGroup', range(line('.'), line('.')))
+
+  " matchend()
+  call assert_equal(4, matchend(range(5), '4'))
+  call assert_equal(3, matchend(range(1, 5), '4'))
+  call assert_equal(-1, matchend(range(1, 5), '42'))
+
+  " matchstrpos()
+  call assert_equal(['4', 4, 0, 1], matchstrpos(range(5), '4'))
+  call assert_equal(['4', 3, 0, 1], matchstrpos(range(1, 5), '4'))
+  call assert_equal(['', -1, -1, -1], matchstrpos(range(1, 5), '42'))
+
+  " max() reverse()
+  call assert_equal(0, max(range(0)))
+  call assert_equal(0, max(range(10, 9)))
+  call assert_equal(9, max(range(10)))
+  call assert_equal(18, max(range(0, 20, 3)))
+  call assert_equal(20, max(range(20, 0, -3)))
+  call assert_equal(99999, max(range(100000)))
+  call assert_equal(99999, max(range(99999, 0, -1)))
+  call assert_equal(99999, max(reverse(range(100000))))
+  call assert_equal(99999, max(reverse(range(99999, 0, -1))))
+
+  " min() reverse()
+  call assert_equal(0, min(range(0)))
+  call assert_equal(0, min(range(10, 9)))
+  call assert_equal(5, min(range(5, 10)))
+  call assert_equal(5, min(range(5, 10, 3)))
+  call assert_equal(2, min(range(20, 0, -3)))
+  call assert_equal(0, min(range(100000)))
+  call assert_equal(0, min(range(99999, 0, -1)))
+  call assert_equal(0, min(reverse(range(100000))))
+  call assert_equal(0, min(reverse(range(99999, 0, -1))))
+
+  " remove()
+  call assert_equal(1, remove(range(1, 10), 0))
+  call assert_equal(2, remove(range(1, 10), 1))
+  call assert_equal(9, remove(range(1, 10), 8))
+  call assert_equal(10, remove(range(1, 10), 9))
+  call assert_equal(10, remove(range(1, 10), -1))
+  call assert_equal([3, 4, 5], remove(range(1, 10), 2, 4))
+
+  " repeat()
+  call assert_equal([0, 1, 2, 0, 1, 2], repeat(range(3), 2))
+  call assert_equal([0, 1, 2], repeat(range(3), 1))
+  call assert_equal([], repeat(range(3), 0))
+  call assert_equal([], repeat(range(5, 4), 2))
+  call assert_equal([], repeat(range(5, 4), 0))
+
+  " reverse()
+  call assert_equal([2, 1, 0], reverse(range(3)))
+  call assert_equal([0, 1, 2, 3], reverse(range(3, 0, -1)))
+  call assert_equal([9, 8, 7, 6, 5, 4, 3, 2, 1, 0], reverse(range(10)))
+  call assert_equal([20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10], reverse(range(10, 20)))
+  call assert_equal([16, 13, 10], reverse(range(10, 18, 3)))
+  call assert_equal([19, 16, 13, 10], reverse(range(10, 19, 3)))
+  call assert_equal([19, 16, 13, 10], reverse(range(10, 20, 3)))
+  call assert_equal([11, 14, 17, 20], reverse(range(20, 10, -3)))
+  call assert_equal([], reverse(range(0)))
+
+  " TODO: setpos()
+  " new
+  " call setline(1, repeat([''], bufnr('')))
+  " call setline(bufnr('') + 1, repeat('x', bufnr('') * 2 + 6))
+  " call setpos('x', range(bufnr(''), bufnr('') + 3))
+  " bwipe!
+
+  " setreg()
+  call setreg('a', range(3))
+  call assert_equal("0\n1\n2\n", getreg('a'))
+
+  " settagstack()
+  call settagstack(1, #{items : range(4)})
+
+  " sign_define()
+  call assert_fails("call sign_define(range(5))", "E715:")
+  call assert_fails("call sign_placelist(range(5))", "E715:")
+
+  " sign_undefine()
+  call assert_fails("call sign_undefine(range(5))", "E908:")
+
+  " sign_unplacelist()
+  call assert_fails("call sign_unplacelist(range(5))", "E715:")
+
+  " sort()
+  call assert_equal([0, 1, 2, 3, 4, 5], sort(range(5, 0, -1)))
+
+  " string()
+  call assert_equal('[0, 1, 2, 3, 4]', string(range(5)))
+
+  " taglist() with 'tagfunc'
+  func TagFunc(pattern, flags, info)
+    return range(10)
+  endfunc
+  set tagfunc=TagFunc
+  call assert_fails("call taglist('asdf')", 'E987:')
+  set tagfunc=
+
+  " term_start()
+  if has('terminal') && has('termguicolors')
+    call assert_fails('call term_start(range(3, 4))', 'E474:')
+    let g:terminal_ansi_colors = range(16)
+    if has('win32')
+      let cmd = "cmd /c dir"
+    else
+      let cmd = "ls"
+    endif
+    call assert_fails('call term_start("' .. cmd .. '", #{term_finish: "close"'
+        \ .. ', ansi_colors: range(16)})', 'E475:')
+    unlet g:terminal_ansi_colors
+  endif
+
+  " type()
+  call assert_equal(v:t_list, type(range(5)))
+
+  " uniq()
+  call assert_equal([0, 1, 2, 3, 4], uniq(range(5)))
+
+  " errors
+  call assert_fails('let x=range(2, 8, 0)', 'E726:')
+  call assert_fails('let x=range(3, 1)', 'E727:')
+  call assert_fails('let x=range(1, 3, -2)', 'E727:')
+  call assert_fails('let x=range([])', 'E745:')
+  call assert_fails('let x=range(1, [])', 'E745:')
+  call assert_fails('let x=range(1, 4, [])', 'E745:')
+endfunc
+
+func Test_garbagecollect_now_fails()
+  let v:testing = 0
+  call assert_fails('call test_garbagecollect_now()', 'E1142:')
+  let v:testing = 1
+endfunc
+
+func Test_echoraw()
+  CheckScreendump
+
+  " Normally used for escape codes, but let's test with a CR.
+  let lines =<< trim END
+    call echoraw("hello\<CR>x")
+  END
+  call writefile(lines, 'XTest_echoraw')
+  let buf = RunVimInTerminal('-S XTest_echoraw', {'rows': 5, 'cols': 40})
+  call VerifyScreenDump(buf, 'Test_functions_echoraw', {})
+
+  " clean up
+  call StopVimInTerminal(buf)
+  call delete('XTest_echoraw')
+endfunc
+
+" Test for echo highlighting
+func Test_echohl()
+  echohl Search
+  echo 'Vim'
+  call assert_equal('Vim', Screenline(&lines))
+  " TODO: How to check the highlight group used by echohl?
+  " ScreenAttrs() returns all zeros.
+  echohl None
+endfunc
+
+" Test for the eval() function
+func Test_eval()
+  call assert_fails("call eval('5 a')", 'E488:')
+endfunc
+
+" Test for the keytrans() function
+func Test_keytrans()
+  call assert_equal('<Space>', keytrans(' '))
+  call assert_equal('<lt>', keytrans('<'))
+  call assert_equal('<lt>Tab>', keytrans('<Tab>'))
+  call assert_equal('<Tab>', keytrans("\<Tab>"))
+  call assert_equal('<C-V>', keytrans("\<C-V>"))
+  call assert_equal('<BS>', keytrans("\<BS>"))
+  call assert_equal('<Home>', keytrans("\<Home>"))
+  call assert_equal('<C-Home>', keytrans("\<C-Home>"))
+  call assert_equal('<M-Home>', keytrans("\<M-Home>"))
+  call assert_equal('<C-Space>', keytrans("\<C-Space>"))
+  call assert_equal('<M-Space>', keytrans("\<*M-Space>"))
+  call assert_equal('<M-x>', "\<*M-x>"->keytrans())
+  call assert_equal('<C-I>', "\<*C-I>"->keytrans())
+  call assert_equal('<S-3>', "\<*S-3>"->keytrans())
+  call assert_equal('π', 'π'->keytrans())
+  call assert_equal('<M-π>', "\<M-π>"->keytrans())
+  call assert_equal('ě', 'ě'->keytrans())
+  call assert_equal('<M-ě>', "\<M-ě>"->keytrans())
+  call assert_equal('', ''->keytrans())
+  call assert_equal('', test_null_string()->keytrans())
+  call assert_fails('call keytrans(1)', 'E1174:')
+  call assert_fails('call keytrans()', 'E119:')
+endfunc
+
+" Test for the nr2char() function
+func Test_nr2char()
+  set encoding=latin1
+  call assert_equal('@', nr2char(64))
+  set encoding=utf8
+  call assert_equal('a', nr2char(97, 1))
+  call assert_equal('a', nr2char(97, 0))
+
+  call assert_equal("\x80\xfc\b" .. nr2char(0x100000), eval('"\<M-' .. nr2char(0x100000) .. '>"'))
+  call assert_equal("\x80\xfc\b" .. nr2char(0x40000000), eval('"\<M-' .. nr2char(0x40000000) .. '>"'))
+endfunc
+
+" Test for screenattr(), screenchar() and screenchars() functions
+func Test_screen_functions()
+  call assert_equal(-1, screenattr(-1, -1))
+  call assert_equal(-1, screenchar(-1, -1))
+  call assert_equal([], screenchars(-1, -1))
+
+  " Run this in a separate Vim instance to avoid messing up.
+  let after =<< trim [CODE]
+    scriptencoding utf-8
+    call setline(1, '口')
+    redraw
+    call assert_equal(0, screenattr(1, 1))
+    call assert_equal(char2nr('口'), screenchar(1, 1))
+    call assert_equal([char2nr('口')], screenchars(1, 1))
+    call assert_equal('口', screenstring(1, 1))
+    call writefile(v:errors, 'Xresult')
+    qall!
+  [CODE]
+
+  let encodings = ['utf-8', 'cp932', 'cp936', 'cp949', 'cp950']
+  if !has('win32')
+    let encodings += ['euc-jp']
+  endif
+  for enc in encodings
+    let msg = 'enc=' .. enc
+    if RunVim([], after, $'--clean --cmd "set encoding={enc}"')
+      call assert_equal([], readfile('Xresult'), msg)
+    endif
+    call delete('Xresult')
+  endfor
+endfunc
+
+" Test for getcurpos() and setpos()
+func Test_getcurpos_setpos()
+  new
+  call setline(1, ['012345678', '012345678'])
+  normal gg6l
+  let sp = getcurpos()
+  normal 0
+  call setpos('.', sp)
+  normal jyl
+  call assert_equal('6', @")
+  call assert_equal(-1, setpos('.', test_null_list()))
+  call assert_equal(-1, setpos('.', {}))
+
+  let winid = win_getid()
+  normal G$
+  let pos = getcurpos()
+  wincmd w
+  call assert_equal(pos, getcurpos(winid))
+
+  wincmd w
+  close!
+
+  call assert_equal(getcurpos(), getcurpos(0))
+  call assert_equal([0, 0, 0, 0, 0], getcurpos(-1))
+  call assert_equal([0, 0, 0, 0, 0], getcurpos(1999))
+endfunc
+
+func Test_getmousepos()
+  enew!
+  call setline(1, "\t\t\t1234")
+  call test_setmouse(1, 1)
+  call assert_equal(#{
+        \ screenrow: 1,
+        \ screencol: 1,
+        \ winid: win_getid(),
+        \ winrow: 1,
+        \ wincol: 1,
+        \ line: 1,
+        \ column: 1,
+        \ }, getmousepos())
+  call test_setmouse(1, 25)
+  call assert_equal(#{
+        \ screenrow: 1,
+        \ screencol: 25,
+        \ winid: win_getid(),
+        \ winrow: 1,
+        \ wincol: 25,
+        \ line: 1,
+        \ column: 4,
+        \ }, getmousepos())
+  call test_setmouse(1, 50)
+  call assert_equal(#{
+        \ screenrow: 1,
+        \ screencol: 50,
+        \ winid: win_getid(),
+        \ winrow: 1,
+        \ wincol: 50,
+        \ line: 1,
+        \ column: 8,
+        \ }, getmousepos())
+
+  " If the mouse is positioned past the last buffer line, "line" and "column"
+  " should act like it's positioned on the last buffer line.
+  call test_setmouse(2, 25)
+  call assert_equal(#{
+        \ screenrow: 2,
+        \ screencol: 25,
+        \ winid: win_getid(),
+        \ winrow: 2,
+        \ wincol: 25,
+        \ line: 1,
+        \ column: 4,
+        \ }, getmousepos())
+  call test_setmouse(2, 50)
+  call assert_equal(#{
+        \ screenrow: 2,
+        \ screencol: 50,
+        \ winid: win_getid(),
+        \ winrow: 2,
+        \ wincol: 50,
+        \ line: 1,
+        \ column: 8,
+        \ }, getmousepos())
+  bwipe!
+endfunc
+
+func Test_getmouseshape()
+  CheckFeature mouseshape
+
+  call assert_equal('arrow', getmouseshape())
+endfunc
+
+" Test for glob()
+func Test_glob()
+  call assert_equal('', glob(test_null_string()))
+  call assert_equal('', globpath(test_null_string(), test_null_string()))
+  call assert_fails("let x = globpath(&rtp, 'syntax/c.vim', [])", 'E745:')
+
+  call writefile([], 'Xglob1')
+  call writefile([], 'XGLOB2')
+  set wildignorecase
+  " Sort output of glob() otherwise we end up with different
+  " ordering depending on whether file system is case-sensitive.
+  call assert_equal(['XGLOB2', 'Xglob1'], sort(glob('Xglob[12]', 0, 1)))
+  " wildignorecase shall be applied even when the pattern contains no wildcards.
+  call assert_equal('XGLOB2', glob('xglob2'))
+  set wildignorecase&
+
+  call delete('Xglob1')
+  call delete('XGLOB2')
+
+  call assert_fails("call glob('*', 0, {})", 'E728:')
+endfunc
+
+" Test for browse()
+func Test_browse()
+  CheckFeature browse
+  call assert_fails('call browse([], "open", "x", "a.c")', 'E745:')
+endfunc
+
+" Test for browsedir()
+func Test_browsedir()
+  CheckFeature browse
+  call assert_fails('call browsedir("open", [])', 'E730:')
+endfunc
+
+func HasDefault(msg = 'msg')
+  return a:msg
+endfunc
+
+func Test_default_arg_value()
+  call assert_equal('msg', HasDefault())
+endfunc
+
+" Test for gettext()
+func Test_gettext()
+  call assert_fails('call gettext(1)', 'E1174:')
+endfunc
+
+func Test_builtin_check()
+  call assert_fails('let g:["trim"] = {x -> " " .. x}', 'E704:')
+  call assert_fails('let g:.trim = {x -> " " .. x}', 'E704:')
+  call assert_fails('let l:["trim"] = {x -> " " .. x}', 'E704:')
+  call assert_fails('let l:.trim = {x -> " " .. x}', 'E704:')
+  let lines =<< trim END
+    vim9script
+    var trim = (x) => " " .. x
+  END
+  call v9.CheckScriptFailure(lines, 'E704:')
+
+  call assert_fails('call extend(g:, #{foo: { -> "foo" }})', 'E704:')
+  let g:bar = 123
+  call extend(g:, #{bar: { -> "foo" }}, "keep")
+  call assert_fails('call extend(g:, #{bar: { -> "foo" }}, "force")', 'E704:')
+  unlet g:bar
+
+  call assert_fails('call extend(l:, #{foo: { -> "foo" }})', 'E704:')
+  let bar = 123
+  call extend(l:, #{bar: { -> "foo" }}, "keep")
+  call assert_fails('call extend(l:, #{bar: { -> "foo" }}, "force")', 'E704:')
+  unlet bar
+
+  call assert_fails('call extend(g:, #{foo: function("extend")})', 'E704:')
+  let g:bar = 123
+  call extend(g:, #{bar: function("extend")}, "keep")
+  call assert_fails('call extend(g:, #{bar: function("extend")}, "force")', 'E704:')
+  unlet g:bar
+
+  call assert_fails('call extend(l:, #{foo: function("extend")})', 'E704:')
+  let bar = 123
+  call extend(l:, #{bar: function("extend")}, "keep")
+  call assert_fails('call extend(l:, #{bar: function("extend")}, "force")', 'E704:')
+  unlet bar
+endfunc
+
+func Test_funcref_to_string()
+  let Fn = funcref('g:Test_funcref_to_string')
+  call assert_equal("function('g:Test_funcref_to_string')", string(Fn))
+endfunc
+
+" Test for isabsolutepath()
+func Test_isabsolutepath()
+  call assert_false(isabsolutepath(''))
+  call assert_false(isabsolutepath('.'))
+  call assert_false(isabsolutepath('../Foo'))
+  call assert_false(isabsolutepath('Foo/'))
+  if has('win32')
+    call assert_true(isabsolutepath('A:\'))
+    call assert_true(isabsolutepath('A:\Foo'))
+    call assert_true(isabsolutepath('A:/Foo'))
+    call assert_false(isabsolutepath('A:Foo'))
+    call assert_false(isabsolutepath('\Windows'))
+    call assert_true(isabsolutepath('\\Server2\Share\Test\Foo.txt'))
+  else
+    call assert_true(isabsolutepath('/'))
+    call assert_true(isabsolutepath('/usr/share/'))
+  endif
+endfunc
+
+" Test for exepath()
+func Test_exepath()
+  if has('win32')
+    call assert_notequal(exepath('cmd'), '')
+
+    let oldNoDefaultCurrentDirectoryInExePath = $NoDefaultCurrentDirectoryInExePath
+    call writefile(['@echo off', 'echo Evil'], 'vim-test-evil.bat')
+    let $NoDefaultCurrentDirectoryInExePath = ''
+    call assert_notequal(exepath("vim-test-evil.bat"), '')
+    let $NoDefaultCurrentDirectoryInExePath = '1'
+    call assert_equal(exepath("vim-test-evil.bat"), '')
+    let $NoDefaultCurrentDirectoryInExePath = oldNoDefaultCurrentDirectoryInExePath
+    call delete('vim-test-evil.bat')
+  else
+    call assert_notequal(exepath('sh'), '')
+  endif
+endfunc
+
+" Test for virtcol()
+func Test_virtcol()
+  enew!
+  call setline(1, "the\tquick\tbrown\tfox")
+  norm! 4|
+  call assert_equal(8, virtcol('.'))
+  call assert_equal(8, virtcol('.', v:false))
+  call assert_equal([4, 8], virtcol('.', v:true))
+  bwipe!
+endfunc
+
+func Test_delfunc_while_listing()
+  CheckRunVimInTerminal
+
+  let lines =<< trim END
+      set nocompatible
+      for i in range(1, 999)
+        exe 'func ' .. 'MyFunc' .. i .. '()'
+        endfunc
+      endfor
+      au CmdlineLeave : call timer_start(0, {-> execute('delfunc MyFunc622')})
+  END
+  call writefile(lines, 'Xfunctionclear', 'D')
+  let buf = RunVimInTerminal('-S Xfunctionclear', {'rows': 12})
+
+  " This was using freed memory.  The height of the terminal must be so that
+  " the next function to be listed with "j" is the one that is deleted in the
+  " timer callback, tricky!
+  call term_sendkeys(buf, ":func /MyFunc\<CR>")
+  call TermWait(buf, 50)
+  call term_sendkeys(buf, "j")
+  call TermWait(buf, 50)
+  call term_sendkeys(buf, "\<CR>")
+
+  call StopVimInTerminal(buf)
+endfunc
+
+" Test for the reverse() function with a string
+func Test_string_reverse()
+  let lines =<< trim END
+    call assert_equal('', reverse(test_null_string()))
+    for [s1, s2] in [['', ''], ['a', 'a'], ['ab', 'ba'], ['abc', 'cba'],
+                   \ ['abcd', 'dcba'], ['«-«-»-»', '»-»-«-«'],
+                   \ ['🇦', '🇦'], ['🇦🇧', '🇧🇦'], ['🇦🇧🇨', '🇨🇧🇦'],
+                   \ ['🇦«🇧-🇨»🇩', '🇩»🇨-🇧«🇦']]
+      call assert_equal(s2, reverse(s1))
+    endfor
+  END
+  call v9.CheckLegacyAndVim9Success(lines)
+
+  " test in latin1 encoding
+  let save_enc = &encoding
+  set encoding=latin1
+  call assert_equal('dcba', reverse('abcd'))
+  let &encoding = save_enc
+endfunc
+
+" vim: shiftwidth=2 sts=2 expandtab