t5100: Avoid filename "nul"

diff --git a/t/t1502-rev-parse-parseopt.sh b/t/t1502-rev-parse-parseopt.sh
index 762af5faf75562cd2a24197eae56357b1443737d..d24a47d1149061565822391542c044a7db193ce5 100755 (executable)
--- a/t/t1502-rev-parse-parseopt.sh
+++ b/t/t1502-rev-parse-parseopt.sh
@@ -37,7 +37,7 @@ C?        option C with an optional argument
 Extras
 extra1    line above used to cause a segfault but no longer does
 EOF
-       git diff expect.err output.err
+       test_cmp expect.err output.err
 '
 
 test_done