diff --git a/test/old/testdir/test_prompt_buffer.vim b/test/old/testdir/test_prompt_buffer.vim
index 2cc3f19b59..3dfbbcece6 100644
--- a/test/old/testdir/test_prompt_buffer.vim
+++ b/test/old/testdir/test_prompt_buffer.vim
@@ -283,20 +283,16 @@ func Test_prompt_appending_while_hidden()
   call TermWait(buf)
 
   call term_sendkeys(buf, "exit\<CR>")
-  call TermWait(buf)
-  call assert_notmatch('-- INSERT --', term_getline(buf, 10))
+  call WaitForAssert({-> assert_notmatch('-- INSERT --', term_getline(buf, 10))})
 
   call term_sendkeys(buf, ":call DoAppend()\<CR>")
-  call TermWait(buf)
-  call assert_notmatch('-- INSERT --', term_getline(buf, 10))
+  call WaitForAssert({-> assert_notmatch('-- INSERT --', term_getline(buf, 10))})
 
   call term_sendkeys(buf, "i")
-  call TermWait(buf)
-  call assert_match('-- INSERT --', term_getline(buf, 10))
+  call WaitForAssert({-> assert_match('-- INSERT --', term_getline(buf, 10))})
 
   call term_sendkeys(buf, "\<C-R>=DoAppend()\<CR>")
-  call TermWait(buf)
-  call assert_match('-- INSERT --', term_getline(buf, 10))
+  call WaitForAssert({-> assert_match('-- INSERT --', term_getline(buf, 10))})
 
   call term_sendkeys(buf, "\<Esc>")
   call StopVimInTerminal(buf)