t5100: Avoid filename "nul"

diff --git a/t/t3900-i18n-commit.sh b/t/t3900-i18n-commit.sh
index 94b1c24b0a3629a6b06466186006a526bb9b4d9d..883281dbd6c02ea7b2d90336c2629eafacee0257 100755 (executable)
--- a/t/t3900-i18n-commit.sh
+++ b/t/t3900-i18n-commit.sh
@@ -9,7 +9,7 @@ test_description='commit and log output encodings'
 
 compare_with () {
        git show -s $1 | sed -e '1,/^$/d' -e 's/^    //' >current &&
-       git diff current "$2"
+       test_cmp current "$2"
 }
 
 test_expect_success setup '