diff --git a/src/testdir/test51.in b/src/testdir/test51.in
index b4f45d1..b66befb 100644
--- a/src/testdir/test51.in
+++ b/src/testdir/test51.in
@@ -24,7 +24,7 @@
 :hi Crash term='asdf
 :redir END
 :" filter ctermfg and ctermbg, the numbers depend on the terminal
-:e test.out
+:e! test.out
 :%s/ctermfg=\d*/ctermfg=2/
 :%s/ctermbg=\d*/ctermbg=3/
 :" filter out possibly translated error message