" Tests for 'backspace' settings

:func Exec(expr)
  let str=''
  try
    exec a:expr
  catch /.*/
    let str=v:exception
  endtry
  return str
:endfunc

func Test_backspace_option()
  set backspace=
  call assert_equal('', &backspace)
  set backspace=indent
  call assert_equal('indent', &backspace)
  set backspace=eol
  call assert_equal('eol', &backspace)
  set backspace=start
  call assert_equal('start', &backspace)
  " Add the value
  set backspace=
  set backspace=indent
  call assert_equal('indent', &backspace)
  set backspace+=eol
  call assert_equal('indent,eol', &backspace)
  set backspace+=start
  call assert_equal('indent,eol,start', &backspace)
  " Delete the value
  set backspace-=indent
  call assert_equal('eol,start', &backspace)
  set backspace-=start
  call assert_equal('eol', &backspace)
  set backspace-=eol
  call assert_equal('', &backspace)
  " Check the error
  call assert_equal(0, match(Exec('set backspace=ABC'), '.*E474'))
  call assert_equal(0, match(Exec('set backspace+=def'), '.*E474'))
  " NOTE: Vim doesn't check following error...
  "call assert_equal(0, match(Exec('set backspace-=ghi'), '.*E474'))

  " Check backwards compatibility with version 5.4 and earlier
  set backspace=0
  call assert_equal('0', &backspace)
  set backspace=1
  call assert_equal('1', &backspace)
  set backspace=2
  call assert_equal('2', &backspace)
  call assert_false(match(Exec('set backspace=3'), '.*E474'))
  call assert_false(match(Exec('set backspace=10'), '.*E474'))

  " Cleared when 'compatible' is set
  set compatible
  call assert_equal('', &backspace)
  set nocompatible
endfunc

" vim: tabstop=2 shiftwidth=0 expandtab