diff --git a/src/testdir/test_edit.vim b/src/testdir/test_edit.vim
index 9096fcd..ce55f6b 100644
--- a/src/testdir/test_edit.vim
+++ b/src/testdir/test_edit.vim
@@ -915,6 +915,23 @@
   bw!
 endfunc
 
+func Test_edit_completefunc_delete()
+  func CompleteFunc(findstart, base)
+    if a:findstart == 1
+      return col('.') - 1
+    endif
+    normal dd
+    return ['a', 'b']
+  endfunc
+  new
+  set completefunc=CompleteFunc
+  call setline(1, ['', 'abcd', ''])
+  2d
+  call assert_fails("normal 2G$a\<C-X>\<C-U>", 'E565:')
+  bwipe!
+endfunc
+
+
 func Test_edit_CTRL_Z()
   " Ctrl-Z when insertmode is not set inserts it literally
   new
@@ -1240,7 +1257,7 @@
   try
     call feedkeys("ix\<esc>", 'tnix')
     call assert_fails(1, 'textlock')
-  catch /^Vim\%((\a\+)\)\=:E523/ " catch E523: not allowed here
+  catch /^Vim\%((\a\+)\)\=:E565/ " catch E565: not allowed here
   endtry
   " TODO: Might be a bug: should x really be inserted here
   call assert_equal(['xa'], getline(1, '$'))
@@ -1264,7 +1281,7 @@
   try
     call feedkeys("i\<c-x>\<c-u>\<esc>", 'tnix')
     call assert_fails(1, 'change in complete function')
-  catch /^Vim\%((\a\+)\)\=:E523/ " catch E523
+  catch /^Vim\%((\a\+)\)\=:E565/ " catch E565
   endtry
   delfu Complete
   set completefunc=
diff --git a/src/testdir/test_ex_mode.vim b/src/testdir/test_ex_mode.vim
index 9f66e3f..d23e0ad 100644
--- a/src/testdir/test_ex_mode.vim
+++ b/src/testdir/test_ex_mode.vim
@@ -158,13 +158,13 @@
 func Test_ex_mode_errors()
   " Not allowed to enter ex mode when text is locked
   au InsertCharPre <buffer> normal! gQ<CR>
-  let caught_e523 = 0
+  let caught_e565 = 0
   try
     call feedkeys("ix\<esc>", 'xt')
-  catch /^Vim\%((\a\+)\)\=:E523/ " catch E523
-    let caught_e523 = 1
+  catch /^Vim\%((\a\+)\)\=:E565/ " catch E565
+    let caught_e565 = 1
   endtry
-  call assert_equal(1, caught_e523)
+  call assert_equal(1, caught_e565)
   au! InsertCharPre
 endfunc
 
diff --git a/src/testdir/test_excmd.vim b/src/testdir/test_excmd.vim
index 9369c1b..868ac6f 100644
--- a/src/testdir/test_excmd.vim
+++ b/src/testdir/test_excmd.vim
@@ -354,15 +354,15 @@
 func Test_run_excmd_with_text_locked()
   " :quit
   let cmd = ":\<C-\>eexecute('quit')\<CR>\<C-C>"
-  call assert_fails("call feedkeys(cmd, 'xt')", 'E523:')
+  call assert_fails("call feedkeys(cmd, 'xt')", 'E565:')
 
   " :qall
   let cmd = ":\<C-\>eexecute('qall')\<CR>\<C-C>"
-  call assert_fails("call feedkeys(cmd, 'xt')", 'E523:')
+  call assert_fails("call feedkeys(cmd, 'xt')", 'E565:')
 
   " :exit
   let cmd = ":\<C-\>eexecute('exit')\<CR>\<C-C>"
-  call assert_fails("call feedkeys(cmd, 'xt')", 'E523:')
+  call assert_fails("call feedkeys(cmd, 'xt')", 'E565:')
 
   " :close - should be ignored
   new
@@ -370,7 +370,7 @@
   call assert_equal(2, winnr('$'))
   close
 
-  call assert_fails("call feedkeys(\":\<C-R>=execute('bnext')\<CR>\", 'xt')", 'E523:')
+  call assert_fails("call feedkeys(\":\<C-R>=execute('bnext')\<CR>\", 'xt')", 'E565:')
 endfunc
 
 " Test for the :verbose command
diff --git a/src/testdir/test_gf.vim b/src/testdir/test_gf.vim
index 829b7c2..736a315 100644
--- a/src/testdir/test_gf.vim
+++ b/src/testdir/test_gf.vim
@@ -134,13 +134,13 @@
 
   " gf is not allowed when text is locked
   au InsertCharPre <buffer> normal! gF<CR>
-  let caught_e523 = 0
+  let caught_e565 = 0
   try
     call feedkeys("ix\<esc>", 'xt')
-  catch /^Vim\%((\a\+)\)\=:E523/ " catch E523
-    let caught_e523 = 1
+  catch /^Vim\%((\a\+)\)\=:E565/ " catch E565
+    let caught_e565 = 1
   endtry
-  call assert_equal(1, caught_e523)
+  call assert_equal(1, caught_e565)
   au! InsertCharPre
 
   bwipe!
diff --git a/src/testdir/test_popup.vim b/src/testdir/test_popup.vim
index e96d5fd..9890377 100644
--- a/src/testdir/test_popup.vim
+++ b/src/testdir/test_popup.vim
@@ -334,19 +334,17 @@
   endif
 endfunc
 
-" Test that nothing happens if the 'completefunc' opens
-" a new window (no completion, no crash)
+" Test that nothing happens if the 'completefunc' tries to open
+" a new window (fails to open window, continues)
 func Test_completefunc_opens_new_window_one()
   new
   let winid = win_getid()
   setlocal completefunc=DummyCompleteOne
   call setline(1, 'one')
   /^one
-  call assert_fails('call feedkeys("A\<C-X>\<C-U>\<C-N>\<Esc>", "x")', 'E839:')
-  call assert_notequal(winid, win_getid())
-  q!
+  call assert_fails('call feedkeys("A\<C-X>\<C-U>\<C-N>\<Esc>", "x")', 'E565:')
   call assert_equal(winid, win_getid())
-  call assert_equal('', getline(1))
+  call assert_equal('oneDEF', getline(1))
   q!
 endfunc