Merge remote-tracking branch 'upstream/master' into usermarksusermarks

1 files changed, 563 insertions, 56 deletions

diff --git a/src/nvim/testdir/test_fold.vim b/src/nvim/testdir/test_fold.vim
index 327f0f73f2..19415286ad 100644
--- a/src/nvim/testdir/test_fold.vim
+++ b/src/nvim/testdir/test_fold.vim
@@ -1,5 +1,6 @@
 " Test for folding
 
+source check.vim
 source view_util.vim
 source screendump.vim
 
@@ -71,6 +72,54 @@ func Test_address_fold()
   quit!
 endfunc
 
+func Test_address_offsets()
+  " check the help for :range-closed-fold
+  enew
+  call setline(1, [
+        \ '1 one',
+        \ '2 two',
+        \ '3 three',
+        \ '4 four FOLDED',
+        \ '5 five FOLDED',
+        \ '6 six',
+        \ '7 seven',
+        \ '8 eight',
+        \])
+  set foldmethod=manual
+  normal 4Gvjzf
+  3,4+2yank
+  call assert_equal([
+        \ '3 three',
+        \ '4 four FOLDED',
+        \ '5 five FOLDED',
+        \ '6 six',
+        \ '7 seven',
+        \ ], getreg(0,1,1))
+
+  enew!
+  call setline(1, [
+        \ '1 one',
+        \ '2 two',
+        \ '3 three FOLDED',
+        \ '4 four FOLDED',
+        \ '5 five FOLDED',
+        \ '6 six FOLDED',
+        \ '7 seven',
+        \ '8 eight',
+        \])
+  normal 3Gv3jzf
+  2,4-1yank
+  call assert_equal([
+        \ '2 two',
+        \ '3 three FOLDED',
+        \ '4 four FOLDED',
+        \ '5 five FOLDED',
+        \ '6 six FOLDED',
+        \ ], getreg(0,1,1))
+
+  bwipe!
+endfunc
+
 func Test_indent_fold()
     new
     call setline(1, ['', 'a', '    b', '    c'])
@@ -93,10 +142,44 @@ func Test_indent_fold2()
     bw!
 endfunc
 
+" Test for fold indent with indents greater than 'foldnestmax'
+func Test_indent_fold_max()
+  new
+  setlocal foldmethod=indent
+  setlocal shiftwidth=2
+  " 'foldnestmax' default value is 20
+  call setline(1, "\t\t\t\t\t\ta")
+  call assert_equal(20, foldlevel(1))
+  setlocal foldnestmax=10
+  call assert_equal(10, foldlevel(1))
+  setlocal foldnestmax=-1
+  call assert_equal(0, foldlevel(1))
+  bw!
+endfunc
+
+func Test_indent_fold_tabstop()
+  call setline(1, ['0', '    1', '    1', "\t2", "\t2"])
+  setlocal shiftwidth=4
+  setlocal foldcolumn=1
+  setlocal foldlevel=2
+  setlocal foldmethod=indent
+  redraw
+  call assert_equal('2        2', ScreenLines(5, 10)[0])
+  vsplit
+  windo diffthis
+  botright new
+  " This 'tabstop' value should not be used for folding in other buffers.
+  setlocal tabstop=4
+  diffoff!
+  redraw
+  call assert_equal('2        2', ScreenLines(5, 10)[0])
+
+  bwipe!
+  bwipe!
+endfunc
+
 func Test_manual_fold_with_filter()
-  if !executable('cat')
-    return
-  endif
+  CheckExecutable cat
   for type in ['manual', 'marker']
     exe 'set foldmethod=' . type
     new
@@ -418,27 +501,6 @@ func Test_move_folds_around_indent()
   bw!
 endfunc
 
-" test for patch 7.3.637
-" Cannot catch the error caused by a foldopen when there is no fold.
-func Test_foldopen_exception()
-  enew!
-  let a = 'No error caught'
-  try
-    foldopen
-  catch
-    let a = matchstr(v:exception,'^[^ ]*')
-  endtry
-  call assert_equal('Vim(foldopen):E490:', a)
-
-  let a = 'No error caught'
-  try
-    foobar
-  catch
-    let a = matchstr(v:exception,'^[^ ]*')
-  endtry
-  call assert_match('E492:', a)
-endfunc
-
 func Test_folddoopen_folddoclosed()
   new
   call setline(1, range(1, 9))
@@ -492,11 +554,24 @@ func Test_fold_error()
   bw!
 endfunc
 
+func Test_foldtext_recursive()
+  new
+  call setline(1, ['{{{', 'some text', '}}}'])
+  setlocal foldenable foldmethod=marker foldtext=foldtextresult(v\:foldstart)
+  " This was crashing because of endless recursion.
+  2foldclose
+  redraw
+  call assert_equal(1, foldlevel(2))
+  call assert_equal(1, foldclosed(2))
+  call assert_equal(3, foldclosedend(2))
+  bwipe!
+endfunc
+
 " Various fold related tests
 
 " Basic test if a fold can be created, opened, moving to the end and closed
 func Test_fold_manual()
-  enew!
+  new
   set fdm=manual
 
   let content = ['1 aa', '2 bb', '3 cc']
@@ -511,13 +586,67 @@ func Test_fold_manual()
   normal zc
   call assert_equal('1 aa', getline(foldclosed('.')))
 
+  " Create a fold inside a closed fold after setting 'foldlevel'
+  %d _
+  call setline(1, range(1, 5))
+  1,5fold
+  normal zR
+  2,4fold
+  set foldlevel=1
+  3fold
+  call assert_equal([1, 3, 3, 3, 1], map(range(1, 5), {->foldlevel(v:val)}))
+  set foldlevel&
+
+  " Create overlapping folds (at the start and at the end)
+  normal zE
+  2,3fold
+  normal zR
+  3,4fold
+  call assert_equal([0, 2, 2, 1, 0], map(range(1, 5), {->foldlevel(v:val)}))
+  normal zE
+  3,4fold
+  normal zR
+  2,3fold
+  call assert_equal([0, 1, 2, 2, 0], map(range(1, 5), {->foldlevel(v:val)}))
+
+  " Create a nested fold across two non-adjoining folds
+  %d _
+  call setline(1, range(1, 7))
+  1,2fold
+  normal zR
+  4,5fold
+  normal zR
+  6,7fold
+  normal zR
+  1,5fold
+  call assert_equal([2, 2, 1, 2, 2, 1, 1],
+        \ map(range(1, 7), {->foldlevel(v:val)}))
+
+  " A newly created nested fold should be closed
+  %d _
+  call setline(1, range(1, 6))
+  1,6fold
+  normal zR
+  3,4fold
+  normal zR
+  2,5fold
+  call assert_equal([1, 2, 3, 3, 2, 1], map(range(1, 6), {->foldlevel(v:val)}))
+  call assert_equal(2, foldclosed(4))
+  call assert_equal(5, foldclosedend(4))
+
+  " Test zO, zC and zA on a line with no folds.
+  normal zE
+  call assert_fails('normal zO', 'E490:')
+  call assert_fails('normal zC', 'E490:')
+  call assert_fails('normal zA', 'E490:')
+
   set fdm&
-  enew!
+  bw!
 endfunc
 
 " test folding with markers.
 func Test_fold_marker()
-  enew!
+  new
   set fdm=marker fdl=1 fdc=3
 
   let content = ['4 dd {{{', '5 ee {{{ }}}', '6 ff }}}']
@@ -531,13 +660,22 @@ func Test_fold_marker()
   normal kYpj
   call assert_equal(0, foldlevel('.'))
 
+  " Use only closing fold marker (without and with a count)
+  set fdl&
+  %d _
+  call setline(1, ['one }}}', 'two'])
+  call assert_equal([0, 0], [foldlevel(1), foldlevel(2)])
+  %d _
+  call setline(1, ['one }}}4', 'two'])
+  call assert_equal([4, 3], [foldlevel(1), foldlevel(2)])
+
   set fdm& fdl& fdc&
-  enew!
+  bw!
 endfunc
 
 " test create fold markers with C filetype
 func Test_fold_create_marker_in_C()
-  enew!
+  bw!
   set fdm=marker fdl=9
   set filetype=c
 
@@ -562,12 +700,12 @@ func Test_fold_create_marker_in_C()
   endfor
 
   set fdm& fdl&
-  enew!
+  bw!
 endfunc
 
 " test folding with indent
 func Test_fold_indent()
-  enew!
+  new
   set fdm=indent sw=2
 
   let content = ['1 aa', '2 bb', '3 cc']
@@ -579,16 +717,14 @@ func Test_fold_indent()
   call assert_equal(1, foldlevel('.'))
 
   set fdm& sw&
-  enew!
+  bw!
 endfunc
 
 " test syntax folding
 func Test_fold_syntax()
-  if !has('syntax')
-    return
-  endif
+  CheckFeature syntax
 
-  enew!
+  new
   set fdm=syntax fdl=0
 
   syn region Hup start="dd" end="ii" fold contains=Fd1,Fd2,Fd3
@@ -612,7 +748,7 @@ func Test_fold_syntax()
   syn clear Fd1 Fd2 Fd3 Hup
 
   set fdm& fdl&
-  enew!
+  bw!
 endfunc
 
 func Flvl()
@@ -631,7 +767,7 @@ endfun
 
 " test expression folding
 func Test_fold_expr()
-  enew!
+  new
   set fdm=expr fde=Flvl()
 
   let content = ['1 aa',
@@ -659,14 +795,14 @@ func Test_fold_expr()
   call assert_equal(0, foldlevel('.'))
 
   set fdm& fde&
-  enew!
+  bw!
 endfunc
 
 " Bug with fdm=indent and moving folds
 " Moving a fold a few times, messes up the folds below the moved fold.
 " Fixed by 7.4.700
 func Test_fold_move()
-  enew!
+  new
   set fdm=indent sw=2 fdl=0
 
   let content = ['', '', 'Line1', '  Line2', '  Line3',
@@ -686,24 +822,33 @@ func Test_fold_move()
   call assert_equal('+--  2 lines: Line8', 10->foldtextresult())
 
   set fdm& sw& fdl&
-  enew!
+  bw!
 endfunc
 
-func Test_foldtext_recursive()
+" test for patch 7.3.637
+" Cannot catch the error caused by a foldopen when there is no fold.
+func Test_foldopen_exception()
   new
-  call setline(1, ['{{{', 'some text', '}}}'])
-  setlocal foldenable foldmethod=marker foldtext=foldtextresult(v\:foldstart)
-  " This was crashing because of endless recursion.
-  2foldclose
-  redraw
-  call assert_equal(1, foldlevel(2))
-  call assert_equal(1, foldclosed(2))
-  call assert_equal(3, foldclosedend(2))
-  bwipe!
+  let a = 'No error caught'
+  try
+    foldopen
+  catch
+    let a = matchstr(v:exception,'^[^ ]*')
+  endtry
+  call assert_equal('Vim(foldopen):E490:', a)
+
+  let a = 'No error caught'
+  try
+    foobar
+  catch
+    let a = matchstr(v:exception,'^[^ ]*')
+  endtry
+  call assert_match('E492:', a)
+  bw!
 endfunc
 
 func Test_fold_last_line_with_pagedown()
-  enew!
+  new
   set fdm=manual
 
   let expect = '+-- 11 lines: 9---'
@@ -723,13 +868,11 @@ func Test_fold_last_line_with_pagedown()
   call assert_equal(expect, ScreenLines(1, len(expect))[0])
 
   set fdm&
-  enew!
+  bw!
 endfunc
 
 func Test_folds_with_rnu()
-  if !CanRunVimInTerminal()
-    throw 'Skipped: cannot make screendumps'
-  endif
+  CheckScreendump
 
   call writefile([
 	\ 'set fdm=marker rnu foldcolumn=2',
@@ -816,6 +959,55 @@ func Test_fold_delete_first_line()
   set foldmethod&
 endfunc
 
+" Add a test for deleting the outer fold of a nested fold and promoting the
+" inner folds to one level up with already a fold at that level following the
+" nested fold.
+func Test_fold_delete_recursive_fold()
+  new
+  call setline(1, range(1, 7))
+  2,3fold
+  normal zR
+  4,5fold
+  normal zR
+  1,5fold
+  normal zR
+  6,7fold
+  normal zR
+  normal 1Gzd
+  normal 1Gzj
+  call assert_equal(2, line('.'))
+  normal zj
+  call assert_equal(4, line('.'))
+  normal zj
+  call assert_equal(6, line('.'))
+  bw!
+endfunc
+
+" Test for errors in 'foldexpr'
+func Test_fold_expr_error()
+  new
+  call setline(1, ['one', 'two', 'three'])
+  " In a window with no folds, foldlevel() should return 0
+  call assert_equal(0, foldlevel(1))
+
+  " Return a list from the expression
+  set foldexpr=[]
+  set foldmethod=expr
+  for i in range(3)
+    call assert_equal(0, foldlevel(i))
+  endfor
+
+  " expression error
+  set foldexpr=[{]
+  set foldmethod=expr
+  for i in range(3)
+    call assert_equal(0, foldlevel(i))
+  endfor
+
+  set foldmethod& foldexpr&
+  close!
+endfunc
+
 func Test_undo_fold_deletion()
   new
   set fdm=marker
@@ -899,6 +1091,264 @@ func Test_fold_relative_move()
   call assert_equal(2, winline())
 
   set fdm& sw& wrap& tw&
+  bw!
+endfunc
+
+" Test for calling foldlevel() from a fold expression
+let g:FoldLevels = []
+func FoldExpr1(lnum)
+  let f = [a:lnum]
+  for i in range(1, line('$'))
+    call add(f, foldlevel(i))
+  endfor
+  call add(g:FoldLevels, f)
+  return getline(a:lnum)[0] == "\t"
+endfunc
+
+func Test_foldexpr_foldlevel()
+  new
+  call setline(1, ['one', "\ttwo", "\tthree"])
+  setlocal foldmethod=expr
+  setlocal foldexpr=FoldExpr1(v:lnum)
+  setlocal foldenable
+  setlocal foldcolumn=3
+  redraw!
+  call assert_equal([[1, -1, -1, -1], [2, -1, -1, -1], [3, 0, 1, -1]],
+        \ g:FoldLevels)
+  set foldmethod& foldexpr& foldenable& foldcolumn&
+  bw!
+endfunc
+
+" Test for returning different values from a fold expression
+func FoldExpr2(lnum)
+  if a:lnum == 1 || a:lnum == 4
+    return -2
+  elseif a:lnum == 2
+    return 'a1'
+  elseif a:lnum == 3
+    return 's4'
+  endif
+  return '='
+endfunc
+
+func Test_foldexpr_2()
+  new
+  call setline(1, ['one', 'two', 'three', 'four'])
+  setlocal foldexpr=FoldExpr2(v:lnum)
+  setlocal foldmethod=expr
+  call assert_equal([0, 1, 1, 0], [foldlevel(1), foldlevel(2), foldlevel(3),
+        \ foldlevel(4)])
+  bw!
+endfunc
+
+" Test for the 'foldclose' option
+func Test_foldclose_opt()
+  CheckScreendump
+
+  let lines =<< trim END
+    set foldmethod=manual foldclose=all foldopen=all
+    call setline(1, ['one', 'two', 'three', 'four'])
+    2,3fold
+    func XsaveFoldLevels()
+      redraw!
+      call writefile([json_encode([foldclosed(1), foldclosed(2), foldclosed(3),
+        \ foldclosed(4)])], 'Xoutput', 'a')
+    endfunc
+  END
+  call writefile(lines, 'Xscript')
+  let rows = 10
+  let buf = RunVimInTerminal('-S Xscript', {'rows': rows})
+  call term_wait(buf)
+  call term_sendkeys(buf, ":set noruler\n")
+  call term_wait(buf)
+  call term_sendkeys(buf, ":call XsaveFoldLevels()\n")
+  call term_sendkeys(buf, "2G")
+  call WaitForAssert({-> assert_equal('two', term_getline(buf, 2))})
+  call term_sendkeys(buf, ":call XsaveFoldLevels()\n")
+  call term_sendkeys(buf, "4G")
+  call WaitForAssert({-> assert_equal('four', term_getline(buf, 3))})
+  call term_sendkeys(buf, ":call XsaveFoldLevels()\n")
+  call term_sendkeys(buf, "3G")
+  call WaitForAssert({-> assert_equal('three', term_getline(buf, 3))})
+  call term_sendkeys(buf, ":call XsaveFoldLevels()\n")
+  call term_sendkeys(buf, "1G")
+  call WaitForAssert({-> assert_equal('four', term_getline(buf, 3))})
+  call term_sendkeys(buf, ":call XsaveFoldLevels()\n")
+  call term_sendkeys(buf, "2G")
+  call WaitForAssert({-> assert_equal('two', term_getline(buf, 2))})
+  call term_sendkeys(buf, "k")
+  call WaitForAssert({-> assert_equal('four', term_getline(buf, 3))})
+
+  " clean up
+  call StopVimInTerminal(buf)
+
+  call assert_equal(['[-1,2,2,-1]', '[-1,-1,-1,-1]', '[-1,2,2,-1]',
+        \ '[-1,-1,-1,-1]', '[-1,2,2,-1]'], readfile('Xoutput'))
+  call delete('Xscript')
+  call delete('Xoutput')
+endfunc
+
+" Test for foldtextresult()
+func Test_foldtextresult()
+  new
+  call assert_equal('', foldtextresult(-1))
+  call assert_equal('', foldtextresult(0))
+  call assert_equal('', foldtextresult(1))
+  call setline(1, ['one', 'two', 'three', 'four'])
+  2,3fold
+  call assert_equal('', foldtextresult(1))
+  call assert_equal('+--  2 lines: two', foldtextresult(2))
+  setlocal foldtext=
+  call assert_equal('+--  2 lines folded ', foldtextresult(2))
+
+  " Fold text for a C comment fold
+  %d _
+  setlocal foldtext&
+  call setline(1, ['', '/*', ' * Comment', ' */', ''])
+  2,4fold
+  call assert_equal('+--  3 lines: Comment', foldtextresult(2))
+
+  bw!
+endfunc
+
+" Test for merging two recursive folds when an intermediate line with no fold
+" is removed
+func Test_fold_merge_recursive()
+  new
+  call setline(1, ['  one', '    two', 'xxxx', '    three',
+        \ '      four', "\tfive"])
+  setlocal foldmethod=indent shiftwidth=2
+  3d_
+  %foldclose
+  call assert_equal([1, 5], [foldclosed(5), foldclosedend(1)])
+  bw!
+endfunc
+
+" Test for moving a line which is the start of a fold from a recursive fold to
+" outside. The fold length should reduce.
+func Test_fold_move_foldlevel()
+  new
+  call setline(1, ['a{{{', 'b{{{', 'c{{{', 'd}}}', 'e}}}', 'f}}}', 'g'])
+  setlocal foldmethod=marker
+  normal zR
+  call assert_equal([3, 2, 1], [foldlevel(4), foldlevel(5), foldlevel(6)])
+  3move 7
+  call assert_equal([2, 1, 0], [foldlevel(3), foldlevel(4), foldlevel(5)])
+  call assert_equal(1, foldlevel(7))
+
+  " Move a line from outside a fold to inside the fold.
+  %d _
+  call setline(1, ['a', 'b{{{', 'c}}}'])
+  normal zR
+  1move 2
+  call assert_equal([1, 1, 1], [foldlevel(1), foldlevel(2), foldlevel(3)])
+
+  " Move the start of one fold to inside another fold
+  %d _
+  call setline(1, ['a', 'b{{{', 'c}}}', 'd{{{', 'e}}}'])
+  normal zR
+  call assert_equal([0, 1, 1, 1, 1], [foldlevel(1), foldlevel(2),
+        \ foldlevel(3), foldlevel(4), foldlevel(5)])
+  1,2move 4
+  call assert_equal([0, 1, 1, 2, 2], [foldlevel(1), foldlevel(2),
+        \ foldlevel(3), foldlevel(4), foldlevel(5)])
+
+  bw!
+endfunc
+
+" Test for using zj and zk to move downwards and upwards to the start and end
+" of the next fold.
+" Test for using [z and ]z in a closed fold to jump to the beginning and end
+" of the fold.
+func Test_fold_jump()
+  new
+  call setline(1, ["\t1", "\t2", "\t\t3", "\t\t4", "\t\t\t5", "\t\t\t6", "\t\t7", "\t\t8", "\t9", "\t10"])
+  setlocal foldmethod=indent
+  normal zR
+  normal zj
+  call assert_equal(3, line('.'))
+  normal zj
+  call assert_equal(5, line('.'))
+  call assert_beeps('normal zj')
+  call assert_equal(5, line('.'))
+  call assert_beeps('normal 9Gzj')
+  call assert_equal(9, line('.'))
+  normal Gzk
+  call assert_equal(8, line('.'))
+  normal zk
+  call assert_equal(6, line('.'))
+  call assert_beeps('normal zk')
+  call assert_equal(6, line('.'))
+  call assert_beeps('normal 2Gzk')
+  call assert_equal(2, line('.'))
+
+  " Using [z or ]z in a closed fold should not move the cursor
+  %d _
+  call setline(1, ["1", "\t2", "\t3", "\t4", "\t5", "\t6", "7"])
+  normal zR4Gzc
+  call assert_equal(4, line('.'))
+  call assert_beeps('normal [z')
+  call assert_equal(4, line('.'))
+  call assert_beeps('normal ]z')
+  call assert_equal(4, line('.'))
+  bw!
+endfunc
+
+" Test for using a script-local function for 'foldexpr'
+func Test_foldexpr_scriptlocal_func()
+  func! s:FoldFunc()
+    let g:FoldLnum = v:lnum
+  endfunc
+  new | only
+  call setline(1, 'abc')
+  let g:FoldLnum = 0
+  set foldmethod=expr foldexpr=s:FoldFunc()
+  redraw!
+  call assert_equal(expand('<SID>') .. 'FoldFunc()', &foldexpr)
+  call assert_equal(1, g:FoldLnum)
+  set foldmethod& foldexpr=
+  bw!
+  new | only
+  call setline(1, 'abc')
+  let g:FoldLnum = 0
+  set foldmethod=expr foldexpr=<SID>FoldFunc()
+  redraw!
+  call assert_equal(expand('<SID>') .. 'FoldFunc()', &foldexpr)
+  call assert_equal(1, g:FoldLnum)
+  set foldmethod& foldexpr=
+  delfunc s:FoldFunc
+  bw!
+endfunc
+
+" Test for using a script-local function for 'foldtext'
+func Test_foldtext_scriptlocal_func()
+  func! s:FoldText()
+    let g:FoldTextArgs = [v:foldstart, v:foldend]
+    return foldtext()
+  endfunc
+  new | only
+  call setline(1, range(50))
+  let g:FoldTextArgs = []
+  set foldmethod=manual
+  set foldtext=s:FoldText()
+  norm! 4Gzf4j
+  redraw!
+  call assert_equal(expand('<SID>') .. 'FoldText()', &foldtext)
+  call assert_equal([4, 8], g:FoldTextArgs)
+  set foldtext&
+  bw!
+  new | only
+  call setline(1, range(50))
+  let g:FoldTextArgs = []
+  set foldmethod=manual
+  set foldtext=<SID>FoldText()
+  norm! 8Gzf4j
+  redraw!
+  call assert_equal(expand('<SID>') .. 'FoldText()', &foldtext)
+  call assert_equal([8, 12], g:FoldTextArgs)
+  set foldtext&
+  bw!
+  delfunc s:FoldText
 endfunc
 
 " Make sure a fold containing a nested fold is split correctly when using
@@ -989,4 +1439,61 @@ func Test_indent_append_blank_small_fold_close()
   bw!
 endfunc
 
+func Test_sort_closed_fold()
+  CheckExecutable sort
+
+  call setline(1, [
+        \ 'Section 1',
+        \ '   how',
+        \ '   now',
+        \ '   brown',
+        \ '   cow',
+        \ 'Section 2',
+        \ '   how',
+        \ '   now',
+        \ '   brown',
+        \ '   cow',
+        \])
+  setlocal foldmethod=indent sw=3
+  normal 2G
+
+  " The "!!" expands to ".,.+3" and must only sort four lines
+  call feedkeys("!!sort\<CR>", 'xt')
+  call assert_equal([
+        \ 'Section 1',
+        \ '   brown',
+        \ '   cow',
+        \ '   how',
+        \ '   now',
+        \ 'Section 2',
+        \ '   how',
+        \ '   now',
+        \ '   brown',
+        \ '   cow',
+        \ ], getline(1, 10))
+
+  bwipe!
+endfunc
+
+func Test_indent_with_L_command()
+  " The "L" command moved the cursor to line zero, causing the text saved for
+  " undo to use line number -1, which caused trouble for undo later.
+  new
+  sil! norm 8R
V{zf8=Lu
+  bwipe!
+endfunc
+
+" Make sure that when there is a fold at the bottom of the buffer and a newline
+" character is appended to the line, the fold gets expanded (instead of the new
+" line not being part of the fold).
+func Test_expand_fold_at_bottom_of_buffer()
+  new
+  " create a fold on the only line
+  fold
+  execute "normal A\<CR>"
+  call assert_equal([1, 1], range(1, 2)->map('foldlevel(v:val)'))
+
+  bwipe!
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab