diff --git a/src/testdir/test_functions.vim b/src/testdir/test_functions.vim
index 4f39d87..e7b81da 100644
--- a/src/testdir/test_functions.vim
+++ b/src/testdir/test_functions.vim
@@ -1331,6 +1331,7 @@
   call feedkeys('a', '')
   call assert_equal(char2nr('a'), getchar())
 
+  call setline(1, 'xxxx')
   call test_setmouse(1, 3)
   let v:mouse_win = 9
   let v:mouse_winid = 9
@@ -1342,6 +1343,7 @@
   call assert_equal(win_getid(1), v:mouse_winid)
   call assert_equal(1, v:mouse_lnum)
   call assert_equal(3, v:mouse_col)
+  enew!
 endfunc
 
 func Test_libcall_libcallnr()