diff --git a/src/testdir/test_winfixbuf.vim b/src/testdir/test_winfixbuf.vim
index 4ee674f..f800338 100644
--- a/src/testdir/test_winfixbuf.vim
+++ b/src/testdir/test_winfixbuf.vim
@@ -2776,11 +2776,11 @@
   call s:make_buffer_pairs()
 
   set winfixbuf
-  call assert_fails("edit something_else", "E1513")
+  call assert_fails("edit something_else", "E1513:")
 
   set nowinfixbuf
   set wfb
-  call assert_fails("edit another_place", "E1513")
+  call assert_fails("edit another_place", "E1513:")
 
   set nowfb
   edit last_place