vim-patch:partial:9.0.0719: too many delete() calls in tests

Problem:    Too many delete() calls in tests.
Solution:   Use deferred delete where possible.

https://github.com/vim/vim/commit/56564964e6d0956c29687e8a10cb94fe42f5c097

This includes all changes expect changes in test_startup.vim.

Co-authored-by: Bram Moolenaar <Bram@vim.org>

19 files changed, 126 insertions, 231 deletions

diff --git a/test/old/testdir/test_scriptnames.vim b/test/old/testdir/test_scriptnames.vim
index 69e5e526fd..13b09a601a 100644
--- a/test/old/testdir/test_scriptnames.vim
+++ b/test/old/testdir/test_scriptnames.vim
@@ -1,7 +1,7 @@
 
 " Test for the :scriptnames command
 func Test_scriptnames()
-  call writefile(['let did_load_script = 123'], 'Xscripting')
+  call writefile(['let did_load_script = 123'], 'Xscripting', 'D')
   source Xscripting
   call assert_equal(123, g:did_load_script)
 
@@ -22,7 +22,6 @@ func Test_scriptnames()
   call assert_equal('Xscripting', expand('%:t'))
 
   bwipe
-  call delete('Xscripting')
 
   let msgs = execute('messages')
   scriptnames
@@ -47,7 +46,7 @@ func Test_getscriptinfo()
     " def Xscript_def_func2()
     " enddef
   END
-  call writefile(lines, 'X22script91')
+  call writefile(lines, 'X22script91', 'D')
   source X22script91
   let l = getscriptinfo()
   call assert_match('X22script91$', l[-1].name)
@@ -103,8 +102,6 @@ func Test_getscriptinfo()
 
   let max_sid = max(map(getscriptinfo(), { k, v -> v.sid }))
   call assert_equal([], getscriptinfo({'sid': max_sid + 1}))
-
-  call delete('X22script91')
 endfunc
 
 " vim: shiftwidth=2 sts=2 expandtab
diff --git a/test/old/testdir/test_search.vim b/test/old/testdir/test_search.vim
index 8b535b5b19..077a7d03a3 100644
--- a/test/old/testdir/test_search.vim
+++ b/test/old/testdir/test_search.vim
@@ -674,7 +674,7 @@ func Test_search_cmdline8()
   endif
   " Prepare buffer text
   let lines = ['abb vim vim vi', 'vimvivim']
-  call writefile(lines, 'Xsearch.txt')
+  call writefile(lines, 'Xsearch.txt', 'D')
   let buf = term_start([GetVimProg(), '--clean', '-c', 'set noswapfile', 'Xsearch.txt'], {'term_rows': 3})
 
   call WaitForAssert({-> assert_equal(lines, [term_getline(buf, 1), term_getline(buf, 2)])})
@@ -693,9 +693,8 @@ func Test_search_cmdline8()
   call assert_notequal(a1, a2)
   call assert_equal(a0, a2)
   call assert_equal(a1, a3)
-  " clean up
-  call delete('Xsearch.txt')
 
+  " clean up
   bwipe!
 endfunc
 
@@ -810,7 +809,7 @@ func Test_search_cmdline_incsearch_highlight_attr()
 
   " Prepare buffer text
   let lines = ['abb vim vim vi', 'vimvivim']
-  call writefile(lines, 'Xsearch.txt')
+  call writefile(lines, 'Xsearch.txt', 'D')
   let buf = term_start([GetVimProg(), '--clean', '-c', 'set noswapfile', 'Xsearch.txt'], {'term_rows': 3})
 
   call WaitForAssert({-> assert_equal(lines, [term_getline(buf, 1), term_getline(buf, 2)])})
@@ -879,9 +878,7 @@ func Test_search_cmdline_incsearch_highlight_attr()
   let attr_line2 = [a0,a0,a0,a0,a0,a0,a0,a0]
   call assert_equal(attr_line1, map(term_scrape(buf, 1)[:len(attr_line1)-1], 'v:val.attr'))
   call assert_equal(attr_line2, map(term_scrape(buf, 2)[:len(attr_line2)-1], 'v:val.attr'))
-  call delete('Xsearch.txt')
 
-  call delete('Xsearch.txt')
   bwipe!
 endfunc
 
@@ -908,7 +905,7 @@ func Test_incsearch_scrolling()
 	\ 'call setline(1, [dots, dots, dots, "", "target", dots, dots])',
 	\ 'normal gg',
 	\ 'redraw',
-	\ ], 'Xscript')
+	\ ], 'Xscript', 'D')
   let buf = RunVimInTerminal('-S Xscript', {'rows': 9, 'cols': 70})
   " Need to send one key at a time to force a redraw
   call term_sendkeys(buf, '/')
@@ -924,7 +921,6 @@ func Test_incsearch_scrolling()
 
   call term_sendkeys(buf, "\<Esc>")
   call StopVimInTerminal(buf)
-  call delete('Xscript')
 endfunc
 
 func Test_incsearch_search_dump()
@@ -937,7 +933,7 @@ func Test_incsearch_search_dump()
 	\ '  call setline(n, "foo " . n)',
 	\ 'endfor',
 	\ '3',
-	\ ], 'Xis_search_script')
+	\ ], 'Xis_search_script', 'D')
   let buf = RunVimInTerminal('-S Xis_search_script', {'rows': 9, 'cols': 70})
   " Give Vim a chance to redraw to get rid of the spaces in line 2 caused by
   " the 'ambiwidth' check.
@@ -954,7 +950,6 @@ func Test_incsearch_search_dump()
   call term_sendkeys(buf, "\<Esc>")
 
   call StopVimInTerminal(buf)
-  call delete('Xis_search_script')
 endfunc
 
 func Test_hlsearch_dump()
@@ -966,7 +961,7 @@ func Test_hlsearch_dump()
         \ 'call setline(1, ["xxx", "xxx", "xxx"])',
 	\ '/.*',
 	\ '2',
-	\ ], 'Xhlsearch_script')
+	\ ], 'Xhlsearch_script', 'D')
   let buf = RunVimInTerminal('-S Xhlsearch_script', {'rows': 6, 'cols': 50})
   call VerifyScreenDump(buf, 'Test_hlsearch_1', {})
 
@@ -974,7 +969,6 @@ func Test_hlsearch_dump()
   call VerifyScreenDump(buf, 'Test_hlsearch_2', {})
 
   call StopVimInTerminal(buf)
-  call delete('Xhlsearch_script')
 endfunc
 
 func Test_hlsearch_and_visual()
@@ -987,14 +981,13 @@ func Test_hlsearch_and_visual()
         \ 'hi Search cterm=bold',
 	\ '/yyy',
 	\ 'call cursor(1, 6)',
-	\ ], 'Xhlvisual_script')
+	\ ], 'Xhlvisual_script', 'D')
   let buf = RunVimInTerminal('-S Xhlvisual_script', {'rows': 6, 'cols': 40})
   call term_sendkeys(buf, "vjj")
   call VerifyScreenDump(buf, 'Test_hlsearch_visual_1', {})
   call term_sendkeys(buf, "\<Esc>")
 
   call StopVimInTerminal(buf)
-  call delete('Xhlvisual_script')
 endfunc
 
 func Test_hlsearch_block_visual_match()
@@ -1004,7 +997,7 @@ func Test_hlsearch_block_visual_match()
     set hlsearch
     call setline(1, ['aa', 'bbbb', 'cccccc'])
   END
-  call writefile(lines, 'Xhlsearch_block')
+  call writefile(lines, 'Xhlsearch_block', 'D')
   let buf = RunVimInTerminal('-S Xhlsearch_block', {'rows': 9, 'cols': 60})
 
   call term_sendkeys(buf, "G\<C-V>$kk\<Esc>")
@@ -1014,7 +1007,6 @@ func Test_hlsearch_block_visual_match()
   call VerifyScreenDump(buf, 'Test_hlsearch_block_visual_match', {})
 
   call StopVimInTerminal(buf)
-  call delete('Xhlsearch_block')
 endfunc
 
 func Test_incsearch_substitute()
@@ -1062,7 +1054,7 @@ func Test_hlsearch_cursearch()
     hi Search ctermbg=yellow
     hi CurSearch ctermbg=blue
   END
-  call writefile(lines, 'Xhlsearch_cursearch')
+  call writefile(lines, 'Xhlsearch_cursearch', 'D')
   let buf = RunVimInTerminal('-S Xhlsearch_cursearch', {'rows': 9, 'cols': 60})
 
   call term_sendkeys(buf, "gg/foo\<CR>")
@@ -1100,7 +1092,6 @@ func Test_hlsearch_cursearch()
   call VerifyScreenDump(buf, 'Test_hlsearch_cursearch_changed_1', {})
 
   call StopVimInTerminal(buf)
-  call delete('Xhlsearch_cursearch')
 endfunc
 
 " Similar to Test_incsearch_substitute() but with a screendump halfway.
@@ -1115,7 +1106,7 @@ func Test_incsearch_substitute_dump()
 	\ 'endfor',
 	\ 'call setline(11, "bar 11")',
 	\ '3',
-	\ ], 'Xis_subst_script')
+	\ ], 'Xis_subst_script', 'D')
   let buf = RunVimInTerminal('-S Xis_subst_script', {'rows': 9, 'cols': 70})
   " Give Vim a chance to redraw to get rid of the spaces in line 2 caused by
   " the 'ambiwidth' check.
@@ -1210,7 +1201,6 @@ func Test_incsearch_substitute_dump()
   call term_sendkeys(buf, "<Esc>")
 
   call StopVimInTerminal(buf)
-  call delete('Xis_subst_script')
 endfunc
 
 func Test_incsearch_highlighting()
@@ -1220,7 +1210,7 @@ func Test_incsearch_highlighting()
   call writefile([
 	\ 'set incsearch hlsearch',
 	\ 'call setline(1, "hello/there")',
-	\ ], 'Xis_subst_hl_script')
+	\ ], 'Xis_subst_hl_script', 'D')
   let buf = RunVimInTerminal('-S Xis_subst_hl_script', {'rows': 4, 'cols': 20})
   " Give Vim a chance to redraw to get rid of the spaces in line 2 caused by
   " the 'ambiwidth' check.
@@ -1233,7 +1223,6 @@ func Test_incsearch_highlighting()
   call term_sendkeys(buf, "<Esc>")
 
   call StopVimInTerminal(buf)
-  call delete('Xis_subst_hl_script')
 endfunc
 
 func Test_incsearch_with_change()
@@ -1245,7 +1234,7 @@ func Test_incsearch_with_change()
 	\ 'set incsearch hlsearch scrolloff=0',
 	\ 'call setline(1, ["one", "two ------ X", "three"])',
 	\ 'call timer_start(200, { _ -> setline(2, "x")})',
-	\ ], 'Xis_change_script')
+	\ ], 'Xis_change_script', 'D')
   let buf = RunVimInTerminal('-S Xis_change_script', {'rows': 9, 'cols': 70})
   " Give Vim a chance to redraw to get rid of the spaces in line 2 caused by
   " the 'ambiwidth' check.
@@ -1257,7 +1246,6 @@ func Test_incsearch_with_change()
   call term_sendkeys(buf, "\<Esc>")
 
   call StopVimInTerminal(buf)
-  call delete('Xis_change_script')
 endfunc
 
 " Similar to Test_incsearch_substitute_dump() for :sort
@@ -1268,7 +1256,7 @@ func Test_incsearch_sort_dump()
   call writefile([
 	\ 'set incsearch hlsearch scrolloff=0',
 	\ 'call setline(1, ["another one 2", "that one 3", "the one 1"])',
-	\ ], 'Xis_sort_script')
+	\ ], 'Xis_sort_script', 'D')
   let buf = RunVimInTerminal('-S Xis_sort_script', {'rows': 9, 'cols': 70})
   " Give Vim a chance to redraw to get rid of the spaces in line 2 caused by
   " the 'ambiwidth' check.
@@ -1283,7 +1271,6 @@ func Test_incsearch_sort_dump()
   call term_sendkeys(buf, "\<Esc>")
 
   call StopVimInTerminal(buf)
-  call delete('Xis_sort_script')
 endfunc
 
 " Similar to Test_incsearch_substitute_dump() for :vimgrep famiry
@@ -1294,7 +1281,7 @@ func Test_incsearch_vimgrep_dump()
   call writefile([
 	\ 'set incsearch hlsearch scrolloff=0',
 	\ 'call setline(1, ["another one 2", "that one 3", "the one 1"])',
-	\ ], 'Xis_vimgrep_script')
+	\ ], 'Xis_vimgrep_script', 'D')
   let buf = RunVimInTerminal('-S Xis_vimgrep_script', {'rows': 9, 'cols': 70})
   " Give Vim a chance to redraw to get rid of the spaces in line 2 caused by
   " the 'ambiwidth' check.
@@ -1322,7 +1309,6 @@ func Test_incsearch_vimgrep_dump()
   call term_sendkeys(buf, "\<Esc>")
 
   call StopVimInTerminal(buf)
-  call delete('Xis_vimgrep_script')
 endfunc
 
 func Test_keep_last_search_pattern()
@@ -1465,11 +1451,9 @@ endfunc
 func Test_no_last_substitute_pat()
   " Use viminfo to set the last search pattern to a string and make the last
   " substitute pattern the most recent used and make it empty (NULL).
-  call writefile(['~MSle0/bar', '~MSle0~&'], 'Xviminfo')
+  call writefile(['~MSle0/bar', '~MSle0~&'], 'Xviminfo', 'D')
   rviminfo! Xviminfo
   call assert_fails('normal n', 'E35:')
-
-  call delete('Xviminfo')
 endfunc
 
 func Test_search_Ctrl_L_combining()
@@ -1676,12 +1660,11 @@ func Test_search_with_no_last_pat()
     call writefile(v:errors, 'Xresult')
     qall!
   [SCRIPT]
-  call writefile(lines, 'Xscript')
+  call writefile(lines, 'Xscript', 'D')
 
   if RunVim([], [], '--clean -S Xscript')
     call assert_equal([], readfile('Xresult'))
   endif
-  call delete('Xscript')
   call delete('Xresult')
 endfunc
 
@@ -1699,11 +1682,10 @@ func Test_search_tilde_pat()
     call writefile(v:errors, 'Xresult')
     qall!
   [SCRIPT]
-  call writefile(lines, 'Xscript')
+  call writefile(lines, 'Xscript', 'D')
   if RunVim([], [], '--clean -S Xscript')
     call assert_equal([], readfile('Xresult'))
   endif
-  call delete('Xscript')
   call delete('Xresult')
 endfunc
 
@@ -1971,7 +1953,7 @@ func Test_incsearch_highlighting_newline()
     set incsearch nohls
     call setline(1, ['test', 'xxx'])
   [CODE]
-  call writefile(commands, 'Xincsearch_nl')
+  call writefile(commands, 'Xincsearch_nl', 'D')
   let buf = RunVimInTerminal('-S Xincsearch_nl', {'rows': 5, 'cols': 10})
   call term_sendkeys(buf, '/test')
   call VerifyScreenDump(buf, 'Test_incsearch_newline1', {})
@@ -1987,7 +1969,6 @@ func Test_incsearch_highlighting_newline()
   call StopVimInTerminal(buf)
 
   " clean up
-  call delete('Xincsearch_nl')
   call test_override("char_avail", 0)
   bw
 endfunc
@@ -2128,11 +2109,10 @@ func Test_search_with_invalid_range()
     5/
     c
   END
-  call writefile(lines, 'Xrangesearch')
+  call writefile(lines, 'Xrangesearch', 'D')
   source Xrangesearch
 
   bwipe!
-  call delete('Xrangesearch')
 endfunc
 
 
diff --git a/test/old/testdir/test_search_stat.vim b/test/old/testdir/test_search_stat.vim
index a2523fc6c7..b57b7ba7b0 100644
--- a/test/old/testdir/test_search_stat.vim
+++ b/test/old/testdir/test_search_stat.vim
@@ -308,7 +308,7 @@ func Test_searchcount_in_statusline()
     set hlsearch
     set laststatus=2 statusline+=%{TestSearchCount()}
   END
-  call writefile(lines, 'Xsearchstatusline')
+  call writefile(lines, 'Xsearchstatusline', 'D')
   let buf = RunVimInTerminal('-S Xsearchstatusline', #{rows: 10})
   call TermWait(buf)
   call term_sendkeys(buf, "/something")
@@ -316,7 +316,6 @@ func Test_searchcount_in_statusline()
 
   call term_sendkeys(buf, "\<Esc>")
   call StopVimInTerminal(buf)
-  call delete('Xsearchstatusline')
 endfunc
 
 func Test_search_stat_foldopen()
@@ -330,7 +329,7 @@ func Test_search_stat_foldopen()
     call cursor(1,1)
     norm n
   END
-  call writefile(lines, 'Xsearchstat1')
+  call writefile(lines, 'Xsearchstat1', 'D')
 
   let buf = RunVimInTerminal('-S Xsearchstat1', #{rows: 10})
   call VerifyScreenDump(buf, 'Test_searchstat_3', {})
@@ -342,7 +341,6 @@ func Test_search_stat_foldopen()
   call VerifyScreenDump(buf, 'Test_searchstat_3', {})
 
   call StopVimInTerminal(buf)
-  call delete('Xsearchstat1')
 endfunc
 
 func! Test_search_stat_screendump()
@@ -359,7 +357,7 @@ func! Test_search_stat_screendump()
     call cursor(1,1)
     norm n
   END
-  call writefile(lines, 'Xsearchstat')
+  call writefile(lines, 'Xsearchstat', 'D')
   let buf = RunVimInTerminal('-S Xsearchstat', #{rows: 10})
   call VerifyScreenDump(buf, 'Test_searchstat_1', {})
 
@@ -368,7 +366,6 @@ func! Test_search_stat_screendump()
   call VerifyScreenDump(buf, 'Test_searchstat_2', {})
 
   call StopVimInTerminal(buf)
-  call delete('Xsearchstat')
 endfunc
 
 func Test_search_stat_then_gd()
@@ -379,7 +376,7 @@ func Test_search_stat_then_gd()
     set shortmess-=S
     set hlsearch
   END
-  call writefile(lines, 'Xsearchstatgd')
+  call writefile(lines, 'Xsearchstatgd', 'D')
 
   let buf = RunVimInTerminal('-S Xsearchstatgd', #{rows: 10})
   call term_sendkeys(buf, "/dog\<CR>")
@@ -389,7 +386,6 @@ func Test_search_stat_then_gd()
   call VerifyScreenDump(buf, 'Test_searchstatgd_2', {})
 
   call StopVimInTerminal(buf)
-  call delete('Xsearchstatgd')
 endfunc
 
 func Test_search_stat_and_incsearch()
diff --git a/test/old/testdir/test_shell.vim b/test/old/testdir/test_shell.vim
index c2320d8f39..9499462a70 100644
--- a/test/old/testdir/test_shell.vim
+++ b/test/old/testdir/test_shell.vim
@@ -188,7 +188,7 @@ func Test_shellxquote()
   let save_sxq = &shellxquote
   let save_sxe = &shellxescape
 
-  call writefile(['#!/bin/sh', 'echo "Cmd: [$*]" > Xlog'], 'Xtestshell')
+  call writefile(['#!/bin/sh', 'echo "Cmd: [$*]" > Xlog'], 'Xtestshell', 'D')
   call setfperm('Xtestshell', "r-x------")
   set shell=./Xtestshell
 
@@ -212,7 +212,6 @@ func Test_shellxquote()
   let &shell = save_shell
   let &shellxquote = save_sxq
   let &shellxescape = save_sxe
-  call delete('Xtestshell')
   call delete('Xlog')
 endfunc
 
diff --git a/test/old/testdir/test_signals.vim b/test/old/testdir/test_signals.vim
index 3ec4b975e1..af4847e42c 100644
--- a/test/old/testdir/test_signals.vim
+++ b/test/old/testdir/test_signals.vim
@@ -118,7 +118,7 @@ func Test_signal_TSTP()
     au VimSuspend * call writefile(["VimSuspend triggered"], "XautoOut1", "as")
     au VimResume * call writefile(["VimResume triggered"], "XautoOut2", "as")
   END
-  call writefile(lines, 'XsetupAucmd')
+  call writefile(lines, 'XsetupAucmd', 'D')
 
   let buf = RunVimInTerminal('-S XsetupAucmd Xsig_TERM', {'rows': 6})
   let pid_vim = term_getjob(buf)->job_info().process
@@ -148,7 +148,6 @@ func Test_signal_TSTP()
 
   %bwipe!
   call delete('.Xsig_TERM.swp')
-  call delete('XsetupAucmd')
   call delete('XautoOut1')
   call delete('XautoOut2')
 endfunc
@@ -177,7 +176,7 @@ func Test_deadly_signal_TERM()
     au VimLeave * call writefile(["VimLeave triggered"], "XautoOut", "as")
     au VimLeavePre * call writefile(["VimLeavePre triggered"], "XautoOut", "as")
   END
-  call writefile(lines, 'XsetupAucmd')
+  call writefile(lines, 'XsetupAucmd', 'D')
 
   let buf = RunVimInTerminal('-S XsetupAucmd Xsig_TERM', {'rows': 6})
   let pid_vim = term_getjob(buf)->job_info().process
@@ -201,7 +200,6 @@ func Test_deadly_signal_TERM()
 
   %bwipe!
   call delete('.Xsig_TERM.swp')
-  call delete('XsetupAucmd')
   call delete('XautoOut')
 endfunc
 
diff --git a/test/old/testdir/test_signs.vim b/test/old/testdir/test_signs.vim
index 1bb2ddd978..4bcf64fbba 100644
--- a/test/old/testdir/test_signs.vim
+++ b/test/old/testdir/test_signs.vim
@@ -254,8 +254,8 @@ func Test_sign_completion()
                 \ 'SpellLocal SpellRare', @:)
   endfor
 
-  call writefile(repeat(["Sun is shining"], 30), "XsignOne")
-  call writefile(repeat(["Sky is blue"], 30), "XsignTwo")
+  call writefile(repeat(["Sun is shining"], 30), "XsignOne", 'D')
+  call writefile(repeat(["Sky is blue"], 30), "XsignTwo", 'D')
   call feedkeys(":sign define Sign icon=Xsig\<C-A>\<C-B>\"\<CR>", 'tx')
   call assert_equal('"sign define Sign icon=XsignOne XsignTwo', @:)
 
@@ -332,8 +332,6 @@ func Test_sign_completion()
   sign undefine Sign1
   sign undefine Sign2
   enew
-  call delete('XsignOne')
-  call delete('XsignTwo')
 endfunc
 
 func Test_sign_invalid_commands()
@@ -476,7 +474,7 @@ func Test_sign_funcs()
   call assert_fails('call sign_getdefined({})', 'E731:')
 
   " Tests for sign_place()
-  call writefile(repeat(["Sun is shining"], 30), "Xsign")
+  call writefile(repeat(["Sun is shining"], 30), "Xsign", 'D')
   edit Xsign
 
   call assert_equal(10, sign_place(10, '', 'sign1', 'Xsign',
@@ -582,7 +580,6 @@ func Test_sign_funcs()
 	      \ 'priority' : 10}]}],
 	      \ sign_getplaced('%', {'lnum' : 22}))
 
-  call delete("Xsign")
   call sign_unplace('*')
   call sign_undefine()
   enew | only
@@ -595,7 +592,7 @@ func Test_sign_group()
   call sign_unplace('*')
   call sign_undefine()
 
-  call writefile(repeat(["Sun is shining"], 30), "Xsign")
+  call writefile(repeat(["Sun is shining"], 30), "Xsign", 'D')
 
   let attr = {'text' : '=>', 'linehl' : 'Search', 'texthl' : 'Error'}
   call assert_equal(0, sign_define("sign1", attr))
@@ -836,7 +833,6 @@ func Test_sign_group()
   " Error cases
   call assert_fails("sign place 3 group= name=sign1 buffer=" . bnum, 'E474:')
 
-  call delete("Xsign")
   call sign_unplace('*')
   call sign_undefine()
   enew | only
@@ -879,8 +875,8 @@ func Test_sign_unplace()
   call sign_undefine()
 
   " Create two files and define signs
-  call writefile(repeat(["Sun is shining"], 30), "Xsign1")
-  call writefile(repeat(["It is beautiful"], 30), "Xsign2")
+  call writefile(repeat(["Sun is shining"], 30), "Xsign1", 'D')
+  call writefile(repeat(["It is beautiful"], 30), "Xsign2", 'D')
 
   let attr = {'text' : '=>', 'linehl' : 'Search', 'texthl' : 'Error'}
   call sign_define("sign1", attr)
@@ -1189,8 +1185,6 @@ func Test_sign_unplace()
   call sign_unplace('*')
   call sign_undefine()
   enew | only
-  call delete("Xsign1")
-  call delete("Xsign2")
 endfunc
 
 " Tests for auto-generating the sign identifier.
@@ -1202,7 +1196,7 @@ func Test_aaa_sign_id_autogen()
   let attr = {'text' : '=>', 'linehl' : 'Search', 'texthl' : 'Error'}
   call assert_equal(0, sign_define("sign1", attr))
 
-  call writefile(repeat(["Sun is shining"], 30), "Xsign")
+  call writefile(repeat(["Sun is shining"], 30), "Xsign", 'D')
   edit Xsign
 
   call assert_equal(1, sign_place(0, '', 'sign1', 'Xsign',
@@ -1224,7 +1218,6 @@ func Test_aaa_sign_id_autogen()
   call assert_equal(10,
 	      \ sign_getplaced('Xsign', {'id' : 1})[0].signs[0].lnum)
 
-  call delete("Xsign")
   call sign_unplace('*')
   call sign_undefine()
   enew | only
@@ -1820,7 +1813,7 @@ func Test_sign_cursor_position()
 	redraw
    	sign place 10 line=2 name=s1
   END
-  call writefile(lines, 'XtestSigncolumn')
+  call writefile(lines, 'XtestSigncolumn', 'D')
   let buf = RunVimInTerminal('-S XtestSigncolumn', {'rows': 6})
   call VerifyScreenDump(buf, 'Test_sign_cursor_1', {})
 
@@ -1840,7 +1833,6 @@ func Test_sign_cursor_position()
 
   " clean up
   call StopVimInTerminal(buf)
-  call delete('XtestSigncolumn')
 endfunc
 
 " Return the 'len' characters in screen starting from (row,col)
@@ -1959,7 +1951,7 @@ endfunc
 
 " Test for managing multiple signs using the sign functions
 func Test_sign_funcs_multi()
-  call writefile(repeat(["Sun is shining"], 30), "Xsign")
+  call writefile(repeat(["Sun is shining"], 30), "Xsign", 'D')
   edit Xsign
   let bnum = bufnr('')
 
@@ -2072,7 +2064,6 @@ func Test_sign_funcs_multi()
   call sign_unplace('*')
   call sign_undefine()
   enew!
-  call delete("Xsign")
 endfunc
 
 func Test_sign_null_list()
diff --git a/test/old/testdir/test_sort.vim b/test/old/testdir/test_sort.vim
index dafa3f618f..2d03dd2f2a 100644
--- a/test/old/testdir/test_sort.vim
+++ b/test/old/testdir/test_sort.vim
@@ -1525,11 +1525,10 @@ func Test_sort_with_no_last_search_pat()
     call writefile(v:errors, 'Xresult')
     qall!
   [SCRIPT]
-  call writefile(lines, 'Xscript')
+  call writefile(lines, 'Xscript', 'D')
   if RunVim([], [], '--clean -S Xscript')
     call assert_equal([], readfile('Xresult'))
   endif
-  call delete('Xscript')
   call delete('Xresult')
 endfunc
 
diff --git a/test/old/testdir/test_source.vim b/test/old/testdir/test_source.vim
index d4d96e36bf..01c08b183c 100644
--- a/test/old/testdir/test_source.vim
+++ b/test/old/testdir/test_source.vim
@@ -53,12 +53,10 @@ endfunc
 " When deleting a file and immediately creating a new one the inode may be
 " recycled.  Vim should not recognize it as the same script.
 func Test_different_script()
-  call writefile(['let s:var = "asdf"'], 'XoneScript')
+  call writefile(['let s:var = "asdf"'], 'XoneScript', 'D')
   source XoneScript
-  call delete('XoneScript')
-  call writefile(['let g:var = s:var'], 'XtwoScript')
+  call writefile(['let g:var = s:var'], 'XtwoScript', 'D')
   call assert_fails('source XtwoScript', 'E121:')
-  call delete('XtwoScript')
 endfunc
 
 " When sourcing a vim script, shebang should be ignored.
diff --git a/test/old/testdir/test_source_utf8.vim b/test/old/testdir/test_source_utf8.vim
index 66fabe0442..f3e11a4bbc 100644
--- a/test/old/testdir/test_source_utf8.vim
+++ b/test/old/testdir/test_source_utf8.vim
@@ -42,7 +42,7 @@ func Test_source_ctrl_v()
         \ "map __3 asd\<C-V>\<C-V>",
         \ "map __4 asd\<C-V>\<C-V>\<C-V>",
         \ "map __5 asd\<C-V>\<C-V>\<C-V>",
-        \ ], 'Xtestfile')
+        \ ], 'Xtestfile', 'D')
   source Xtestfile
   enew!
   exe "normal __1\<Esc>\<Esc>__2\<Esc>__3\<Esc>\<Esc>__4\<Esc>__5\<Esc>"
@@ -52,7 +52,6 @@ func Test_source_ctrl_v()
         \ getline(1, 2))
 
   enew!
-  call delete('Xtestfile')
   unmap __1
   unmap __2
   unmap __3
diff --git a/test/old/testdir/test_spell.vim b/test/old/testdir/test_spell.vim
index 643744d817..bdd8a673fd 100644
--- a/test/old/testdir/test_spell.vim
+++ b/test/old/testdir/test_spell.vim
@@ -812,8 +812,8 @@ func Test_zz_sal_and_addition()
   throw 'skipped: Nvim does not support enc=latin1'
   set enc=latin1
   set spellfile=
-  call writefile(g:test_data_dic1, "Xtest.dic")
-  call writefile(g:test_data_aff_sal, "Xtest.aff")
+  call writefile(g:test_data_dic1, "Xtest.dic", 'D')
+  call writefile(g:test_data_aff_sal, "Xtest.aff", 'D')
   mkspell! Xtest Xtest
   set spl=Xtest.latin1.spl spell
   call assert_equal('kbltykk', soundfold('goobledygoook'))
@@ -821,7 +821,7 @@ func Test_zz_sal_and_addition()
   call assert_equal('*fls kswts tl', soundfold('oeverloos gezwets edale'))
 
   "also use an addition file
-  call writefile(["/regions=usgbnz", "elequint/2", "elekwint/3"], "Xtest.latin1.add")
+  call writefile(["/regions=usgbnz", "elequint/2", "elekwint/3"], "Xtest.latin1.add", 'D')
   mkspell! Xtest.latin1.add.spl Xtest.latin1.add
 
   bwipe!
@@ -858,10 +858,9 @@ endfunc
 
 func Test_region_error()
   messages clear
-  call writefile(["/regions=usgbnz", "elequint/0"], "Xtest.latin1.add")
+  call writefile(["/regions=usgbnz", "elequint/0"], "Xtest.latin1.add", 'D')
   mkspell! Xtest.latin1.add.spl Xtest.latin1.add
   call assert_match('Invalid region nr in Xtest.latin1.add line 2: 0', execute('messages'))
-  call delete('Xtest.latin1.add')
   call delete('Xtest.latin1.add.spl')
 endfunc
 
diff --git a/test/old/testdir/test_spell_utf8.vim b/test/old/testdir/test_spell_utf8.vim
index 91ada1ed38..bb2c354a3d 100644
--- a/test/old/testdir/test_spell_utf8.vim
+++ b/test/old/testdir/test_spell_utf8.vim
@@ -726,8 +726,8 @@ endfunc
 " Test with SAL instead of SOFO items; test automatic reloading
 func Test_spell_sal_and_addition()
   set spellfile=
-  call writefile(g:test_data_dic1, "Xtest.dic")
-  call writefile(g:test_data_aff_sal, "Xtest.aff")
+  call writefile(g:test_data_dic1, "Xtest.dic", 'D')
+  call writefile(g:test_data_aff_sal, "Xtest.aff", 'D')
   mkspell! Xtest Xtest
   set spl=Xtest.utf-8.spl spell
   call assert_equal('kbltykk', soundfold('goobledygoook'))
@@ -735,7 +735,7 @@ func Test_spell_sal_and_addition()
   call assert_equal('*fls kswts tl', soundfold('oeverloos gezwets edale'))
 
   "also use an addition file
-  call writefile(["/regions=usgbnz", "elequint/2", "elekwint/3"], "Xtest.utf-8.add")
+  call writefile(["/regions=usgbnz", "elequint/2", "elekwint/3"], "Xtest.utf-8.add", 'D')
   mkspell! Xtest.utf-8.add.spl Xtest.utf-8.add
 
   bwipe!
diff --git a/test/old/testdir/test_spellfile.vim b/test/old/testdir/test_spellfile.vim
index 50621144bd..09b69dd93c 100644
--- a/test/old/testdir/test_spellfile.vim
+++ b/test/old/testdir/test_spellfile.vim
@@ -212,7 +212,7 @@ endfunc
 " The spell file format is described in spellfile.c
 func Test_spellfile_format_error()
   let save_rtp = &rtp
-  call mkdir('Xtest/spell', 'p')
+  call mkdir('Xtest/spell', 'pR')
   let splfile = './Xtest/spell/Xtest.utf-8.spl'
 
   " empty spell file
@@ -384,13 +384,12 @@ func Test_spellfile_format_error()
   call Spellfile_Test(0zFF00000000000000000000000201010000, 'E759:')
 
   let &rtp = save_rtp
-  call delete('Xtest', 'rf')
 endfunc
 
 " Test for format errors in suggest file
 func Test_sugfile_format_error()
   let save_rtp = &rtp
-  call mkdir('Xtest/spell', 'p')
+  call mkdir('Xtest/spell', 'pR')
   let splfile = './Xtest/spell/Xtest.utf-8.spl'
   let sugfile = './Xtest/spell/Xtest.utf-8.sug'
 
@@ -473,7 +472,6 @@ func Test_sugfile_format_error()
   set nospell spelllang&
 
   let &rtp = save_rtp
-  call delete('Xtest', 'rf')
 endfunc
 
 " Test for using :mkspell to create a spell file from a list of words
@@ -486,7 +484,7 @@ func Test_wordlist_dic()
     /encoding=latin1
     example
   [END]
-  call writefile(lines, 'Xwordlist.dic')
+  call writefile(lines, 'Xwordlist.dic', 'D')
   let output = execute('mkspell Xwordlist.spl Xwordlist.dic')
   call assert_match('Duplicate /encoding= line ignored in Xwordlist.dic line 4: /encoding=latin1', output)
 
@@ -559,7 +557,6 @@ func Test_wordlist_dic()
   call assert_match('Compressed keep-case:', output)
 
   call delete('Xwordlist.spl')
-  call delete('Xwordlist.dic')
 endfunc
 
 " Test for the :mkspell command
@@ -600,8 +597,8 @@ func Test_aff_file_format_error()
   CheckNotMSWindows
 
   " No word count in .dic file
-  call writefile([], 'Xtest.dic')
-  call writefile([], 'Xtest.aff')
+  call writefile([], 'Xtest.dic', 'D')
+  call writefile([], 'Xtest.aff', 'D')
   call assert_fails('mkspell! Xtest.spl Xtest', 'E760:')
 
   " create a .dic file for the tests below
@@ -823,20 +820,14 @@ func Test_aff_file_format_error()
 
   " use multiple .aff files with different values for COMPOUNDWORDMAX and
   " MIDWORD (number and string)
-  call writefile(['1', 'world'], 'Xtest_US.dic')
-  call writefile(['1', 'world'], 'Xtest_CA.dic')
-  call writefile(["COMPOUNDWORDMAX 3", "MIDWORD '-"], 'Xtest_US.aff')
-  call writefile(["COMPOUNDWORDMAX 4", "MIDWORD '="], 'Xtest_CA.aff')
+  call writefile(['1', 'world'], 'Xtest_US.dic', 'D')
+  call writefile(['1', 'world'], 'Xtest_CA.dic', 'D')
+  call writefile(["COMPOUNDWORDMAX 3", "MIDWORD '-"], 'Xtest_US.aff', 'D')
+  call writefile(["COMPOUNDWORDMAX 4", "MIDWORD '="], 'Xtest_CA.aff', 'D')
   let output = execute('mkspell! Xtest.spl Xtest_US Xtest_CA')
   call assert_match('COMPOUNDWORDMAX value differs from what is used in another .aff file', output)
   call assert_match('MIDWORD value differs from what is used in another .aff file', output)
-  call delete('Xtest_US.dic')
-  call delete('Xtest_CA.dic')
-  call delete('Xtest_US.aff')
-  call delete('Xtest_CA.aff')
 
-  call delete('Xtest.dic')
-  call delete('Xtest.aff')
   call delete('Xtest.spl')
   call delete('Xtest.sug')
 endfunc
@@ -856,8 +847,8 @@ func Test_spell_add_word()
 endfunc
 
 func Test_spellfile_verbose()
-  call writefile(['1', 'one'], 'XtestVerbose.dic')
-  call writefile([], 'XtestVerbose.aff')
+  call writefile(['1', 'one'], 'XtestVerbose.dic', 'D')
+  call writefile([], 'XtestVerbose.aff', 'D')
   mkspell! XtestVerbose-utf8.spl XtestVerbose
   set spell
 
@@ -870,15 +861,13 @@ func Test_spellfile_verbose()
   call assert_notmatch('Reading spell file "XtestVerbose-utf8.spl"', a)
 
   set spell& spelllang&
-  call delete('XtestVerbose.dic')
-  call delete('XtestVerbose.aff')
   call delete('XtestVerbose-utf8.spl')
 endfunc
 
 " Test NOBREAK (see :help spell-NOBREAK)
 func Test_NOBREAK()
-  call writefile(['3', 'one', 'two', 'three' ], 'XtestNOBREAK.dic')
-  call writefile(['NOBREAK' ], 'XtestNOBREAK.aff')
+  call writefile(['3', 'one', 'two', 'three' ], 'XtestNOBREAK.dic', 'D')
+  call writefile(['NOBREAK' ], 'XtestNOBREAK.aff', 'D')
 
   mkspell! XtestNOBREAK-utf8.spl XtestNOBREAK
   set spell spelllang=XtestNOBREAK-utf8.spl
@@ -900,8 +889,6 @@ func Test_NOBREAK()
 
   bw!
   set spell& spelllang&
-  call delete('XtestNOBREAK.dic')
-  call delete('XtestNOBREAK.aff')
   call delete('XtestNOBREAK-utf8.spl')
 endfunc
 
@@ -911,11 +898,11 @@ func Test_spellfile_CHECKCOMPOUNDPATTERN()
         \         'one/c',
         \         'two/c',
         \         'three/c',
-        \         'four'], 'XtestCHECKCOMPOUNDPATTERN.dic')
+        \         'four'], 'XtestCHECKCOMPOUNDPATTERN.dic', 'D')
   " Forbid compound words where first word ends with 'wo' and second starts with 'on'.
   call writefile(['CHECKCOMPOUNDPATTERN 1',
         \         'CHECKCOMPOUNDPATTERN wo on',
-        \         'COMPOUNDFLAG c'], 'XtestCHECKCOMPOUNDPATTERN.aff')
+        \         'COMPOUNDFLAG c'], 'XtestCHECKCOMPOUNDPATTERN.aff', 'D')
 
   mkspell! XtestCHECKCOMPOUNDPATTERN-utf8.spl XtestCHECKCOMPOUNDPATTERN
   set spell spelllang=XtestCHECKCOMPOUNDPATTERN-utf8.spl
@@ -939,8 +926,6 @@ func Test_spellfile_CHECKCOMPOUNDPATTERN()
   endfor
 
   set spell& spelllang&
-  call delete('XtestCHECKCOMPOUNDPATTERN.dic')
-  call delete('XtestCHECKCOMPOUNDPATTERN.aff')
   call delete('XtestCHECKCOMPOUNDPATTERN-utf8.spl')
 endfunc
 
@@ -949,15 +934,15 @@ func Test_spellfile_NOCOMPOUNDSUGS()
   call writefile(['3',
         \         'one/c',
         \         'two/c',
-        \         'three/c'], 'XtestNOCOMPOUNDSUGS.dic')
+        \         'three/c'], 'XtestNOCOMPOUNDSUGS.dic', 'D')
 
   " pass 0 tests without NOCOMPOUNDSUGS, pass 1 tests with NOCOMPOUNDSUGS
   for pass in [0, 1]
     if pass == 0
-      call writefile(['COMPOUNDFLAG c'], 'XtestNOCOMPOUNDSUGS.aff')
+      call writefile(['COMPOUNDFLAG c'], 'XtestNOCOMPOUNDSUGS.aff', 'D')
     else
       call writefile(['NOCOMPOUNDSUGS',
-          \           'COMPOUNDFLAG c'], 'XtestNOCOMPOUNDSUGS.aff')
+          \           'COMPOUNDFLAG c'], 'XtestNOCOMPOUNDSUGS.aff', 'D')
     endif
 
     mkspell! XtestNOCOMPOUNDSUGS-utf8.spl XtestNOCOMPOUNDSUGS
@@ -985,8 +970,6 @@ func Test_spellfile_NOCOMPOUNDSUGS()
   endfor
 
   set spell& spelllang&
-  call delete('XtestNOCOMPOUNDSUGS.dic')
-  call delete('XtestNOCOMPOUNDSUGS.aff')
   call delete('XtestNOCOMPOUNDSUGS-utf8.spl')
 endfunc
 
@@ -999,8 +982,8 @@ func Test_spellfile_COMMON()
         \         'any',
         \         'tee',
         \         'the',
-        \         'ted'], 'XtestCOMMON.dic')
-  call writefile(['COMMON the and'], 'XtestCOMMON.aff')
+        \         'ted'], 'XtestCOMMON.dic', 'D')
+  call writefile(['COMMON the and'], 'XtestCOMMON.aff', 'D')
 
   mkspell! XtestCOMMON-utf8.spl XtestCOMMON
   set spell spelllang=XtestCOMMON-utf8.spl
@@ -1012,15 +995,13 @@ func Test_spellfile_COMMON()
   call assert_equal(['the', 'tee'], spellsuggest('dhe', 2))
 
   set spell& spelllang&
-  call delete('XtestCOMMON.dic')
-  call delete('XtestCOMMON.aff')
   call delete('XtestCOMMON-utf8.spl')
 endfunc
 
 " Test NOSUGGEST (see :help spell-COMMON)
 func Test_spellfile_NOSUGGEST()
-  call writefile(['2', 'foo/X', 'fog'], 'XtestNOSUGGEST.dic')
-  call writefile(['NOSUGGEST X'], 'XtestNOSUGGEST.aff')
+  call writefile(['2', 'foo/X', 'fog'], 'XtestNOSUGGEST.dic', 'D')
+  call writefile(['NOSUGGEST X'], 'XtestNOSUGGEST.aff', 'D')
 
   mkspell! XtestNOSUGGEST-utf8.spl XtestNOSUGGEST
   set spell spelllang=XtestNOSUGGEST-utf8.spl
@@ -1038,8 +1019,6 @@ func Test_spellfile_NOSUGGEST()
   call assert_equal(['fog'], spellsuggest('fogg', 1))
 
   set spell& spelllang&
-  call delete('XtestNOSUGGEST.dic')
-  call delete('XtestNOSUGGEST.aff')
   call delete('XtestNOSUGGEST-utf8.spl')
 endfunc
 
@@ -1048,7 +1027,7 @@ endfunc
 func Test_spellfile_CIRCUMFIX()
   " Example taken verbatim from https://github.com/hunspell/hunspell/tree/master/tests
   call writefile(['1',
-        \         'nagy/C	po:adj'], 'XtestCIRCUMFIX.dic')
+        \         'nagy/C	po:adj'], 'XtestCIRCUMFIX.dic', 'D')
   call writefile(['# circumfixes: ~ obligate prefix/suffix combinations',
         \         '# superlative in Hungarian: leg- (prefix) AND -bb (suffix)',
         \         '',
@@ -1063,7 +1042,7 @@ func Test_spellfile_CIRCUMFIX()
         \         'SFX C Y 3',
         \         'SFX C 0 obb . is:COMPARATIVE',
         \         'SFX C 0 obb/AX . is:SUPERLATIVE',
-        \         'SFX C 0 obb/BX . is:SUPERSUPERLATIVE'], 'XtestCIRCUMFIX.aff')
+        \         'SFX C 0 obb/BX . is:SUPERSUPERLATIVE'], 'XtestCIRCUMFIX.aff', 'D')
 
   mkspell! XtestCIRCUMFIX-utf8.spl XtestCIRCUMFIX
   set spell spelllang=XtestCIRCUMFIX-utf8.spl
@@ -1082,8 +1061,6 @@ func Test_spellfile_CIRCUMFIX()
   endfor
 
   set spell& spelllang&
-  call delete('XtestCIRCUMFIX.dic')
-  call delete('XtestCIRCUMFIX.aff')
   call delete('XtestCIRCUMFIX-utf8.spl')
 endfunc
 
@@ -1095,12 +1072,12 @@ func Test_spellfile_SFX_strip()
         \         'SFX A are hiamo [cg]are',
         \         'SFX A re mo iare',
         \         'SFX A re vamo are'],
-        \         'XtestSFX.aff')
+        \         'XtestSFX.aff', 'D')
   " Examples of Italian verbs:
   " - cantare = to sing
   " - cercare = to search
   " - odiare = to hate
-  call writefile(['3', 'cantare/A', 'cercare/A', 'odiare/A'], 'XtestSFX.dic')
+  call writefile(['3', 'cantare/A', 'cercare/A', 'odiare/A'], 'XtestSFX.dic', 'D')
 
   mkspell! XtestSFX-utf8.spl XtestSFX
   set spell spelllang=XtestSFX-utf8.spl
@@ -1124,8 +1101,6 @@ func Test_spellfile_SFX_strip()
   call assert_equal(['odiamo'],    spellsuggest('odiiamo', 1))
 
   set spell& spelllang&
-  call delete('XtestSFX.dic')
-  call delete('XtestSFX.aff')
   call delete('XtestSFX-utf8.spl')
 endfunc
 
@@ -1134,7 +1109,7 @@ endfunc
 func Test_init_spellfile()
   let save_rtp = &rtp
   let save_encoding = &encoding
-  call mkdir('Xrtp/spell', 'p')
+  call mkdir('Xrtp/spell', 'pR')
   call writefile(['vim'], 'Xrtp/spell/Xtest.dic')
   silent mkspell Xrtp/spell/Xtest.utf-8.spl Xrtp/spell/Xtest.dic
   set runtimepath=./Xrtp
@@ -1144,8 +1119,8 @@ func Test_init_spellfile()
   call assert_equal('./Xrtp/spell/Xtest.utf-8.add', &spellfile)
   call assert_equal(['abc'], readfile('Xrtp/spell/Xtest.utf-8.add'))
   call assert_true(filereadable('Xrtp/spell/Xtest.utf-8.spl'))
+
   set spell& spelllang& spellfile&
-  call delete('Xrtp', 'rf')
   let &encoding = save_encoding
   let &rtp = save_rtp
   %bw!
@@ -1171,12 +1146,10 @@ endfunc
 
 " this was using a NULL pointer
 func Test_mkspell_empty_dic()
-  call writefile(['1'], 'XtestEmpty.dic')
-  call writefile(['SOFOFROM abcd', 'SOFOTO ABCD', 'SAL CIA X'], 'XtestEmpty.aff')
+  call writefile(['1'], 'XtestEmpty.dic', 'D')
+  call writefile(['SOFOFROM abcd', 'SOFOTO ABCD', 'SAL CIA X'], 'XtestEmpty.aff', 'D')
   mkspell! XtestEmpty.spl XtestEmpty
 
-  call delete('XtestEmpty.dic')
-  call delete('XtestEmpty.aff')
   call delete('XtestEmpty.spl')
 endfunc
 
diff --git a/test/old/testdir/test_startup_utf8.vim b/test/old/testdir/test_startup_utf8.vim
index 1684d80c80..e8b99e7937 100644
--- a/test/old/testdir/test_startup_utf8.vim
+++ b/test/old/testdir/test_startup_utf8.vim
@@ -6,7 +6,7 @@ source screendump.vim
 
 func Test_read_stdin_utf8()
   let linesin = ['テスト', '€ÀÈÌÒÙ']
-  call writefile(linesin, 'Xtestin')
+  call writefile(linesin, 'Xtestin', 'D')
   let before = [
 	\ 'set enc=utf-8',
 	\ 'set fencs=cp932,utf-8',
@@ -26,24 +26,22 @@ func Test_read_stdin_utf8()
   else
     call assert_equal('', 'RunVimPiped failed.')
   endif
+
   call delete('Xtestout')
-  call delete('Xtestin')
 endfunc
 
 func Test_read_fifo_utf8()
-  if !has('unix')
-    return
-  endif
+  CheckUnix
   " Using bash/zsh's process substitution.
   if executable('bash')
     set shell=bash
   elseif executable('zsh')
     set shell=zsh
   else
-    return
+    throw 'Skipped: bash or zsh is required'
   endif
   let linesin = ['テスト', '€ÀÈÌÒÙ']
-  call writefile(linesin, 'Xtestin')
+  call writefile(linesin, 'Xtestin', 'D')
   let before = [
 	\ 'set enc=utf-8',
 	\ 'set fencs=cp932,utf-8',
@@ -58,8 +56,8 @@ func Test_read_fifo_utf8()
   else
     call assert_equal('', 'RunVim failed.')
   endif
+
   call delete('Xtestout')
-  call delete('Xtestin')
 endfunc
 
 func Test_detect_ambiwidth()
@@ -71,12 +69,13 @@ func Test_detect_ambiwidth()
 	\ 'set ambiwidth=double',
 	\ 'call test_option_not_set("ambiwidth")',
 	\ 'redraw',
-	\ ], 'Xscript')
+	\ ], 'Xscript', 'D')
   let buf = RunVimInTerminal('-S Xscript', #{keep_t_u7: 1})
   call TermWait(buf)
   call term_sendkeys(buf, "S\<C-R>=&ambiwidth\<CR>\<Esc>")
   call WaitForAssert({-> assert_match('single', term_getline(buf, 1))})
 
   call StopVimInTerminal(buf)
-  call delete('Xscript')
 endfunc
+
+" vim: shiftwidth=2 sts=2 expandtab
diff --git a/test/old/testdir/test_stat.vim b/test/old/testdir/test_stat.vim
index 13ade5bee1..b9fd7f5f28 100644
--- a/test/old/testdir/test_stat.vim
+++ b/test/old/testdir/test_stat.vim
@@ -63,7 +63,7 @@ func Test_checktime()
   let fname = 'Xtest.tmp'
 
   let fl = ['Hello World!']
-  call writefile(fl, fname)
+  call writefile(fl, fname, 'D')
   set autoread
   exec 'e' fname
   call SleepForTimestamp()
@@ -72,8 +72,6 @@ func Test_checktime()
   call writefile(fl, fname)
   checktime
   call assert_equal(fl[0], getline(1))
-
-  call delete(fname)
 endfunc
 
 func Test_checktime_fast()
@@ -82,7 +80,7 @@ func Test_checktime_fast()
   let fname = 'Xtest.tmp'
 
   let fl = ['Hello World!']
-  call writefile(fl, fname)
+  call writefile(fl, fname, 'D')
   set autoread
   exec 'e' fname
   let fl = readfile(fname)
@@ -91,8 +89,6 @@ func Test_checktime_fast()
   call writefile(fl, fname)
   checktime
   call assert_equal(fl[0], getline(1))
-
-  call delete(fname)
 endfunc
 
 func Test_autoread_fast()
@@ -106,12 +102,10 @@ func Test_autoread_fast()
   call setline(1, 'foo')
   w!
   sleep 10m
-  call writefile(['bar'], 'Xautoread')
+  call writefile(['bar'], 'Xautoread', 'D')
   sleep 10m
   checktime
   call assert_equal('bar', trim(getline(1)))
-
-  call delete('Xautoread')
 endfunc
 
 func Test_autoread_file_deleted()
diff --git a/test/old/testdir/test_statusline.vim b/test/old/testdir/test_statusline.vim
index c48bac12b4..f8c326bb41 100644
--- a/test/old/testdir/test_statusline.vim
+++ b/test/old/testdir/test_statusline.vim
@@ -483,14 +483,13 @@ func Test_statusline_removed_group()
     set laststatus=2
     let &statusline = '%#StatColorHi2#%(✓%#StatColorHi2#%) Q≡'
   END
-  call writefile(lines, 'XTest_statusline')
+  call writefile(lines, 'XTest_statusline', 'D')
 
   let buf = RunVimInTerminal('-S XTest_statusline', {'rows': 10, 'cols': 50})
   call VerifyScreenDump(buf, 'Test_statusline_1', {})
 
   " clean up
   call StopVimInTerminal(buf)
-  call delete('XTest_statusline')
 endfunc
 
 func Test_statusline_using_mode()
@@ -501,7 +500,7 @@ func Test_statusline_using_mode()
     split
     setlocal statusline=+%{mode()}+
   END
-  call writefile(lines, 'XTest_statusline')
+  call writefile(lines, 'XTest_statusline', 'D')
 
   let buf = RunVimInTerminal('-S XTest_statusline', {'rows': 7, 'cols': 50})
   call VerifyScreenDump(buf, 'Test_statusline_mode_1', {})
@@ -512,7 +511,6 @@ func Test_statusline_using_mode()
   " clean up
   call term_sendkeys(buf, "close\<CR>")
   call StopVimInTerminal(buf)
-  call delete('XTest_statusline')
 endfunc
 
 func Test_statusline_after_split_vsplit()
@@ -567,13 +565,12 @@ func Test_statusline_highlight_truncate()
     hi! link User2 ErrorMsg
     set statusline=%.5(%1*ABC%2*DEF%1*GHI%)
   END
-  call writefile(lines, 'XTest_statusline')
+  call writefile(lines, 'XTest_statusline', 'D')
 
   let buf = RunVimInTerminal('-S XTest_statusline', {'rows': 6})
   call VerifyScreenDump(buf, 'Test_statusline_hl', {})
 
   call StopVimInTerminal(buf)
-  call delete('XTest_statusline')
 endfunc
 
 func Test_statusline_showcmd()
diff --git a/test/old/testdir/test_substitute.vim b/test/old/testdir/test_substitute.vim
index fdb0f6fc37..a8f2d99f50 100644
--- a/test/old/testdir/test_substitute.vim
+++ b/test/old/testdir/test_substitute.vim
@@ -892,7 +892,7 @@ func Test_sub_with_no_last_pat()
     call writefile(v:errors, 'Xresult')
     qall!
   [SCRIPT]
-  call writefile(lines, 'Xscript')
+  call writefile(lines, 'Xscript', 'D')
   if RunVim([], [], '--clean -S Xscript')
     call assert_equal([], readfile('Xresult'))
   endif
@@ -909,7 +909,6 @@ func Test_sub_with_no_last_pat()
   "   call assert_equal([], readfile('Xresult'))
   " endif
 
-  call delete('Xscript')
   call delete('Xresult')
 endfunc
 
@@ -1110,13 +1109,12 @@ func Test_sub_open_cmdline_win()
     redir END
     qall!
   [SCRIPT]
-  call writefile(lines, 'Xscript')
+  call writefile(lines, 'Xscript', 'D')
   if RunVim([], [], '-u NONE -S Xscript')
     call assert_match('E565: Not allowed to change text or change window',
           \ readfile('Xresult')->join('XX'))
   endif
 
-  call delete('Xscript')
   call delete('Xresult')
 endfunc
 
diff --git a/test/old/testdir/test_swap.vim b/test/old/testdir/test_swap.vim
index 65b6c57850..7c84c47337 100644
--- a/test/old/testdir/test_swap.vim
+++ b/test/old/testdir/test_swap.vim
@@ -10,14 +10,13 @@ endfunc
 
 " Tests for 'directory' option.
 func Test_swap_directory()
-  if !has("unix")
-    return
-  endif
+  CheckUnix
+
   let content = ['start of testfile',
 	      \ 'line 2 Abcdefghij',
 	      \ 'line 3 Abcdefghij',
 	      \ 'end of testfile']
-  call writefile(content, 'Xtest1')
+  call writefile(content, 'Xtest1', 'D')
 
   "  '.', swap file in the same directory as file
   set dir=.,~
@@ -31,7 +30,7 @@ func Test_swap_directory()
   " './dir', swap file in a directory relative to the file
   set dir=./Xtest2,.,~
 
-  call mkdir("Xtest2")
+  call mkdir("Xtest2", 'R')
   edit Xtest1
   call assert_equal([], glob(swfname, 1, 1, 1))
   let swfname = "Xtest2/Xtest1.swp"
@@ -41,7 +40,7 @@ func Test_swap_directory()
   " 'dir', swap file in directory relative to the current dir
   set dir=Xtest.je,~
 
-  call mkdir("Xtest.je")
+  call mkdir("Xtest.je", 'R')
   call writefile(content, 'Xtest2/Xtest3')
   edit Xtest2/Xtest3
   call assert_equal(["Xtest2/Xtest3"], glob("Xtest2/*", 1, 1, 1))
@@ -50,15 +49,11 @@ func Test_swap_directory()
   call assert_equal([swfname], glob("Xtest.je/*", 1, 1, 1))
 
   set dir&
-  call delete("Xtest1")
-  call delete("Xtest2", "rf")
-  call delete("Xtest.je", "rf")
 endfunc
 
 func Test_swap_group()
-  if !has("unix")
-    return
-  endif
+  CheckUnix
+
   let groups = split(system('groups'))
   if len(groups) <= 1
     throw 'Skipped: need at least two groups, got ' . string(groups)
@@ -148,7 +143,7 @@ func Test_swapinfo()
   let info = swapinfo('doesnotexist')
   call assert_equal('Cannot open file', info.error)
 
-  call writefile(['burp'], 'Xnotaswapfile')
+  call writefile(['burp'], 'Xnotaswapfile', 'D')
   let info = swapinfo('Xnotaswapfile')
   call assert_equal('Cannot read file', info.error)
   call delete('Xnotaswapfile')
@@ -156,7 +151,6 @@ func Test_swapinfo()
   call writefile([repeat('x', 10000)], 'Xnotaswapfile')
   let info = swapinfo('Xnotaswapfile')
   call assert_equal('Not a swap file', info.error)
-  call delete('Xnotaswapfile')
 endfunc
 
 func Test_swapname()
@@ -204,7 +198,7 @@ func Test_swapfile_delete()
   " Close the file and recreate the swap file.
   " Now editing the file will run into the process still existing
   quit
-  call writefile(swapfile_bytes, swapfile_name)
+  call writefile(swapfile_bytes, swapfile_name, 'D')
   let s:swap_choice = 'e'
   let s:swapname = ''
   split XswapfileText
@@ -232,7 +226,6 @@ func Test_swapfile_delete()
   call assert_equal(fnamemodify(swapfile_name, ':t'), fnamemodify(s:swapname, ':t'))
 
   call delete('XswapfileText')
-  call delete(swapfile_name)
   augroup test_swapfile_delete
     autocmd!
   augroup END
@@ -246,7 +239,7 @@ func Test_swap_recover()
     autocmd SwapExists * let v:swapchoice = 'r'
   augroup END
 
-  call mkdir('Xswap')
+  call mkdir('Xswap', 'R')
   let $Xswap = 'foo'  " Check for issue #4369.
   set dir=Xswap//
   " Create a valid swapfile by editing a file.
@@ -259,7 +252,7 @@ func Test_swap_recover()
 
   " Close the file and recreate the swap file.
   quit
-  call writefile(swapfile_bytes, swapfile_name)
+  call writefile(swapfile_bytes, swapfile_name, 'D')
   " Edit the file again. This triggers recovery.
   try
     split Xswap/text
@@ -271,9 +264,6 @@ func Test_swap_recover()
   call assert_equal(['one', 'two', 'three'], getline(1, 3))
   quit!
 
-  call delete('Xswap/text')
-  call delete(swapfile_name)
-  call delete('Xswap', 'd')
   unlet $Xswap
   set dir&
   augroup test_swap_recover
@@ -301,7 +291,7 @@ func Test_swap_recover_ext()
   " Close and delete the file and recreate the swap file.
   quit
   call delete('Xtest.scr')
-  call writefile(swapfile_bytes, swapfile_name)
+  call writefile(swapfile_bytes, swapfile_name, 'D')
   " Edit the file again. This triggers recovery.
   try
     split Xtest.scr
@@ -314,7 +304,6 @@ func Test_swap_recover_ext()
   quit!
 
   call delete('Xtest.scr')
-  call delete(swapfile_name)
   augroup test_swap_recover_ext
     autocmd!
   augroup END
@@ -342,7 +331,7 @@ func Test_swap_split_win()
   " Close and delete the file and recreate the swap file.
   quit
   call delete('Xtest.scr')
-  call writefile(swapfile_bytes, swapfile_name)
+  call writefile(swapfile_bytes, swapfile_name, 'D')
   " Split edit the file again. This should fail to open the window
   try
     split Xtest.scr
@@ -353,7 +342,6 @@ func Test_swap_split_win()
   call assert_equal(1, winnr('$'))
 
   call delete('Xtest.scr')
-  call delete(swapfile_name)
 
   augroup test_swap_splitwin
       autocmd!
@@ -365,7 +353,7 @@ endfunc
 func Test_swap_prompt_splitwin()
   CheckRunVimInTerminal
 
-  call writefile(['foo bar'], 'Xfile1')
+  call writefile(['foo bar'], 'Xfile1', 'D')
   edit Xfile1
   preserve  " should help to make sure the swap file exists
 
@@ -400,13 +388,12 @@ func Test_swap_prompt_splitwin()
   call StopVimInTerminal(buf)
 
   %bwipe!
-  call delete('Xfile1')
 endfunc
 
 func Test_swap_symlink()
   CheckUnix
 
-  call writefile(['text'], 'Xtestfile')
+  call writefile(['text'], 'Xtestfile', 'D')
   silent !ln -s -f Xtestfile Xtestlink
 
   set dir=.
@@ -417,7 +404,7 @@ func Test_swap_symlink()
   call assert_match('Xtestfile\.swp$', s:swapname())
   bwipe!
 
-  call mkdir('Xswapdir')
+  call mkdir('Xswapdir', 'R')
   exe 'set dir=' . getcwd() . '/Xswapdir//'
 
   " Check that this also works when 'directory' ends with '//'
@@ -426,9 +413,7 @@ func Test_swap_symlink()
   bwipe!
 
   set dir&
-  call delete('Xtestfile')
   call delete('Xtestlink')
-  call delete('Xswapdir', 'rf')
 endfunc
 
 func s:get_unused_pid(base)
@@ -486,7 +471,7 @@ func Test_swap_auto_delete()
   " Change the process ID to avoid the "still running" warning.
   let swapfile_bytes[24:27] = s:pid_to_blob(s:get_unused_pid(
         \ s:blob_to_pid(swapfile_bytes[24:27])))
-  call writefile(swapfile_bytes, swapfile_name)
+  call writefile(swapfile_bytes, swapfile_name, 'D')
   edit Xtest.scr
   " will end up using the same swap file after deleting the existing one
   call assert_equal(swapfile_name, swapname('%'))
@@ -510,7 +495,6 @@ func Test_swap_auto_delete()
   bwipe!
 
   call delete('Xtest.scr')
-  call delete(swapfile_name)
   augroup test_swap_recover_ext
     autocmd!
   augroup END
@@ -539,13 +523,13 @@ endfunc
 
 " Test for the v:swapchoice variable
 func Test_swapchoice()
-  call writefile(['aaa', 'bbb'], 'Xfile5')
+  call writefile(['aaa', 'bbb'], 'Xfile5', 'D')
   edit Xfile5
   preserve
   let swapfname = swapname('')
   let b = readblob(swapfname)
   bw!
-  call writefile(b, swapfname)
+  call writefile(b, swapfname, 'D')
 
   autocmd! SwapExists
 
@@ -584,7 +568,6 @@ func Test_swapchoice()
   %bw!
   call assert_false(filereadable(swapfname))
 
-  call delete('Xfile5')
   call delete(swapfname)
   augroup test_swapchoice
     autocmd!
diff --git a/test/old/testdir/test_syntax.vim b/test/old/testdir/test_syntax.vim
index 8a24c4ae27..207efb6223 100644
--- a/test/old/testdir/test_syntax.vim
+++ b/test/old/testdir/test_syntax.vim
@@ -644,15 +644,16 @@ func Test_syntax_c()
 	\ '   printf("Just an example piece of C code\n");',
 	\ '   return 0x0ff;',
 	\ '}',
+	\ "\t\t ",
 	\ '   static void',
 	\ 'myFunction(const double count, struct nothing, long there) {',
-	\ '  // 123: nothing to read here',
-	\ '  for (int i = 0; i < count; ++i) {',
-	\ '    break;',
-	\ '  }',
-	\ "  Note: asdf",
+	\ "\t// 123: nothing to endif here",
+	\ "\tfor (int i = 0; i < count; ++i) {",
+	\ "\t   break;",
+	\ "\t}",
+	\ "\tNote: asdf",
 	\ '}',
-	\ ], 'Xtest.c')
+	\ ], 'Xtest.c', 'D')
 
   " This makes the default for 'background' use "dark", check that the
   " response to t_RB corrects it to "light".
@@ -664,7 +665,6 @@ func Test_syntax_c()
   call StopVimInTerminal(buf)
 
   let $COLORFGBG = ''
-  call delete('Xtest.c')
 endfun
 
 " Test \z(...) along with \z1
@@ -698,10 +698,10 @@ func Test_syn_wrong_z_one()
 endfunc
 
 func Test_syntax_after_bufdo()
-  call writefile(['/* aaa comment */'], 'Xaaa.c')
-  call writefile(['/* bbb comment */'], 'Xbbb.c')
-  call writefile(['/* ccc comment */'], 'Xccc.c')
-  call writefile(['/* ddd comment */'], 'Xddd.c')
+  call writefile(['/* aaa comment */'], 'Xaaa.c', 'D')
+  call writefile(['/* bbb comment */'], 'Xbbb.c', 'D')
+  call writefile(['/* ccc comment */'], 'Xccc.c', 'D')
+  call writefile(['/* ddd comment */'], 'Xddd.c', 'D')
 
   let bnr = bufnr('%')
   new Xaaa.c
@@ -729,10 +729,6 @@ func Test_syntax_after_bufdo()
   bwipe! Xccc.c
   bwipe! Xddd.c
   syntax off
-  call delete('Xaaa.c')
-  call delete('Xbbb.c')
-  call delete('Xccc.c')
-  call delete('Xddd.c')
 endfunc
 
 func Test_syntax_foldlevel()
diff --git a/test/old/testdir/test_system.vim b/test/old/testdir/test_system.vim
index 6c8373b335..30fab6d55f 100644
--- a/test/old/testdir/test_system.vim
+++ b/test/old/testdir/test_system.vim
@@ -53,7 +53,7 @@ func Test_system_exmode()
     let cmd = ' -es -c "source Xscript" +q; echo "result=$?"'
     " Need to put this in a script, "catch" isn't found after an unknown
     " function.
-    call writefile(['try', 'call doesnotexist()', 'catch', 'endtry'], 'Xscript')
+    call writefile(['try', 'call doesnotexist()', 'catch', 'endtry'], 'Xscript', 'D')
     let a = system(GetVimCommand() . cmd)
     call assert_match('result=0', a)
     call assert_equal(0, v:shell_error)
@@ -69,7 +69,6 @@ func Test_system_exmode()
   let cmd = ' -es -c "source Xscript" +q'
   let a = system(GetVimCommand() . cmd)
   call assert_notequal(0, v:shell_error)
-  call delete('Xscript')
 
   if has('unix') " echo $? only works on Unix
     let cmd = ' -es -c "call doesnotexist()" +q; echo $?'