new file mode 100644
--- /dev/null
+++ b/src/testdir/test82.in
@@ -0,0 +1,93 @@
+Tests for case-insensitive UTF-8 comparisons (utf_strnicmp() in mbyte.c)
+
+STARTTEST
+:so small.vim
+:if !has("multi_byte")
+: e! test.ok
+: w! test.out
+: qa!
+:endif
+:set enc=utf8
+ggdG
+:
+:function! Ch(a, op, b, expected)
+:  if eval(printf('"%s" %s "%s"', a:a, a:op, a:b)) != a:expected
+:    call append(line('$'), printf('"%s" %s "%s" should return %d', a:a, a:op, a:b, a:expected))
+:  else
+:    let b:passed += 1
+:  endif
+:endfunction
+:
+:function! Chk(a, b, result)
+:  if a:result == 0
+:    call Ch(a:a, '==?', a:b, 1)
+:    call Ch(a:a, '!=?', a:b, 0)
+:    call Ch(a:a, '<=?', a:b, 1)
+:    call Ch(a:a, '>=?', a:b, 1)
+:    call Ch(a:a, '<?', a:b, 0)
+:    call Ch(a:a, '>?', a:b, 0)
+:  elseif a:result > 0
+:    call Ch(a:a, '==?', a:b, 0)
+:    call Ch(a:a, '!=?', a:b, 1)
+:    call Ch(a:a, '<=?', a:b, 0)
+:    call Ch(a:a, '>=?', a:b, 1)
+:    call Ch(a:a, '<?', a:b, 0)
+:    call Ch(a:a, '>?', a:b, 1)
+:  else
+:    call Ch(a:a, '==?', a:b, 0)
+:    call Ch(a:a, '!=?', a:b, 1)
+:    call Ch(a:a, '<=?', a:b, 1)
+:    call Ch(a:a, '>=?', a:b, 0)
+:    call Ch(a:a, '<?', a:b, 1)
+:    call Ch(a:a, '>?', a:b, 0)
+:  endif
+:endfunction
+:
+:function! Check(a, b, result)
+:  call Chk(a:a, a:b, a:result)
+:  call Chk(a:b, a:a, -a:result)
+:endfunction
+:
+:function! LT(a, b)
+:  call Check(a:a, a:b, -1)
+:endfunction
+:
+:function! GT(a, b)
+:  call Check(a:a, a:b, 1)
+:endfunction
+:
+:function! EQ(a, b)
+:  call Check(a:a, a:b, 0)
+:endfunction
+:
+:let b:passed=0
+:call EQ('', '')
+:call LT('', 'a')
+:call EQ('abc', 'abc')
+:call EQ('Abc', 'abC')
+:call LT('ab', 'abc')
+:call LT('AB', 'abc')
+:call LT('ab', 'aBc')
+:call EQ('\xd0\xb9\xd1\x86\xd1\x83\xd0\xba\xd0\xb5\xd0\xbd', '\xd0\xb9\xd0\xa6\xd0\xa3\xd0\xba\xd0\x95\xd0\xbd')
+:call LT('\xd0\xb9\xd1\x86\xd1\x83\xd0\xba\xd0\xb5\xd0\xbd', '\xd0\xaf\xd1\x86\xd1\x83\xd0\xba\xd0\xb5\xd0\xbd')
+:call EQ('\xe2\x84\xaa', 'k')
+:call LT('\xe2\x84\xaa', 'kkkkkk')
+:call EQ('\xe2\x84\xaa\xe2\x84\xaa\xe2\x84\xaa', 'kkk')
+:call LT('kk', '\xe2\x84\xaa\xe2\x84\xaa\xe2\x84\xaa')
+:call EQ('\xe2\x84\xaa\xe2\x84\xa6k\xe2\x84\xaak\xcf\x89', 'k\xcf\x89\xe2\x84\xaakk\xe2\x84\xa6')
+:call EQ('Abc\x80', 'AbC\x80')
+:call LT('Abc\x80', 'AbC\x81')
+:call LT('Abc', 'AbC\x80')
+:call LT('abc\x80DEF', 'abc\x80def')  " case folding stops at the first bad character
+:call LT('\xc3XYZ', '\xc3xyz')
+:call EQ('\xef\xbc\xba', '\xef\xbd\x9a')  " FF3A (upper), FF5A (lower)
+:call GT('\xef\xbc\xba', '\xef\xbc\xff')  " first string is ok and equals \xef\xbd\x9a after folding, second string is illegal and was left unchanged, then the strings were bytewise compared
+:call LT('\xc3', '\xc3\x83')
+:call EQ('\xc3\xa3xYz', '\xc3\x83XyZ')
+:for n in range(0x60, 0xFF) | call LT(printf('xYz\x%.2X', n-1), printf('XyZ\x%.2X', n)) | endfor
+:for n in range(0x80, 0xBF) | call EQ(printf('xYz\xc2\x%.2XUvW', n), printf('XyZ\xc2\x%.2XuVw', n)) | endfor
+:for n in range(0xC0, 0xFF) | call LT(printf('xYz\xc2\x%.2XUvW', n), printf('XyZ\xc2\x%.2XuVw', n)) | endfor
+:call append(0, printf('%d checks passed', b:passed))
+:wq! test.out
+ENDTEST
+