diff --git a/test/functional/legacy/conceal_spec.lua b/test/functional/legacy/conceal_spec.lua
index 66a99fe684..6c347eac85 100644
--- a/test/functional/legacy/conceal_spec.lua
+++ b/test/functional/legacy/conceal_spec.lua
@@ -393,7 +393,7 @@ describe('Conceal', function()
             \ "three |hidden| three three three three three three three three"]
       call setline(1, lines)
       set wrap linebreak
-      set showbreak=\ >>>\ 
+      let &showbreak = ' >>> '
       syntax match test /|hidden|/ conceal
       set conceallevel=2
       set concealcursor=
diff --git a/test/old/testdir/test_conceal.vim b/test/old/testdir/test_conceal.vim
index 5448e9a991..a992baf008 100644
--- a/test/old/testdir/test_conceal.vim
+++ b/test/old/testdir/test_conceal.vim
@@ -148,7 +148,7 @@ func Test_conceal_with_cursorcolumn()
           \ "three |hidden| three three three three three three three three"]
     call setline(1, lines)
     set wrap linebreak
-    set showbreak=\ >>>\ 
+    let &showbreak = ' >>> '
     syntax match test /|hidden|/ conceal
     set conceallevel=2
     set concealcursor=
diff --git a/test/old/testdir/test_display.vim b/test/old/testdir/test_display.vim
index 09f33cb2f2..4a0f56be3d 100644
--- a/test/old/testdir/test_display.vim
+++ b/test/old/testdir/test_display.vim
@@ -345,7 +345,7 @@ func Test_eob_fillchars()
   set fillchars=eob:+
   redraw
   call assert_equal('+', Screenline(2))
-  set fillchars=eob:\ 
+  let &fillchars = 'eob: '
   redraw
   call assert_equal(' ', nr2char(screenchar(2, 1)))
   set fillchars&
@@ -416,7 +416,7 @@ func Test_fold_fillchars()
   call assert_equal(expected, lines)
 
   " check setting foldinner
-  set fillchars+=foldinner:\ 
+  let &fillchars = &fillchars .. ',foldinner: '
   let lines = ScreenLines([1, 6], 22)
   let expected = [
         \ ' one                  ',
diff --git a/test/old/testdir/test_ins_complete.vim b/test/old/testdir/test_ins_complete.vim
index 78810f64f4..ce0a45f808 100644
--- a/test/old/testdir/test_ins_complete.vim
+++ b/test/old/testdir/test_ins_complete.vim
@@ -3421,7 +3421,9 @@ endfunc
 func Test_ins_complete_end_of_line()
   " this was reading past the end of the line
   new
-  norm 8o€ý 
+  " Note that the 'space' at the end of the expression below is a non-breaking
+  " space, U+00a0.
+  execute "norm 8o€ý "
   sil! norm o
 
   bwipe!
diff --git a/test/old/testdir/test_listchars.vim b/test/old/testdir/test_listchars.vim
index d6a1be235c..279d10d57d 100644
--- a/test/old/testdir/test_listchars.vim
+++ b/test/old/testdir/test_listchars.vim
@@ -422,7 +422,7 @@ func Test_listchars()
 
   " Test leadtab with pipe character
   normal ggdG
-  set listchars=tab:>-,leadtab:\|\ 
+  let &listchars = 'tab:>-,leadtab:| '
   call append(0, ["\ttext"])
   let expected = ['|       text']
   call Check_listchars(expected, 1, 12)
@@ -430,7 +430,7 @@ func Test_listchars()
 
   " Test leadtab with unicode bar
   normal ggdG
-  set listchars=tab:>-,leadtab:│\ 
+  let &listchars = 'tab:>-,leadtab:│ '
   call append(0, ["\ttext"])
   let expected = ['│       text']
   call Check_listchars(expected, 1, 12)
diff --git a/test/old/testdir/test_normal.vim b/test/old/testdir/test_normal.vim
index 7513c2fe16..18cbc0b20b 100644
--- a/test/old/testdir/test_normal.vim
+++ b/test/old/testdir/test_normal.vim
@@ -4447,6 +4447,7 @@ endfunc
 "
 " The problem occurred because WM_SETFOCUS was processed slowly, and typebuf
 " was not empty when it should have been.
+" TODO: Is this test flaky?
 func Test_win32_gui_setfocus_prevent_showcmd()
   if !has('win32') || !has('gui_running')
     throw 'Skipped: Windows GUI regression test'
diff --git a/test/old/testdir/test_scroll_opt.vim b/test/old/testdir/test_scroll_opt.vim
index eb073d3628..4db7db2a49 100644
--- a/test/old/testdir/test_scroll_opt.vim
+++ b/test/old/testdir/test_scroll_opt.vim
@@ -518,7 +518,8 @@ func Test_smoothscroll_long_line_showbreak()
       vim9script
       # a line that spans four screen lines
       setline(1, 'with lots of text in one line '->repeat(6))
-      set smoothscroll scrolloff=0 showbreak=+++\ 
+      set smoothscroll scrolloff=0
+      &showbreak = '+++ '
   END
   call writefile(lines, 'XSmoothLongShowbreak', 'D')
   let buf = RunVimInTerminal('-S XSmoothLongShowbreak', #{rows: 6, cols: 40})
diff --git a/test/old/testdir/test_signs.vim b/test/old/testdir/test_signs.vim
index 5fd2590b89..6db31af13a 100644
--- a/test/old/testdir/test_signs.vim
+++ b/test/old/testdir/test_signs.vim
@@ -167,7 +167,9 @@ func Test_sign()
 
   sign define Sign5 text=X\  linehl=Comment
   sign undefine Sign5
-  sign define Sign5 linehl=Comment text=X\ 
+  " The use of execute in the next line is just to ensure the space for
+  " the text value is obvious and does not get accidently deleted.
+  execute "sign define Sign5 linehl=Comment text=X\ "
   sign undefine Sign5
 
   " define sign with backslash