diff --git a/t/t5100-mailinfo.sh b/t/t5100-mailinfo.sh
index a8b78ebf7d021cb626d4452545b5f4d1e0efe34f..577ecc210a55a5da10552a4415c4cbb5e321039b 100755
--- a/t/t5100-mailinfo.sh
+++ b/t/t5100-mailinfo.sh
@@ -27,8 +27,8 @@ done
 
 test_expect_success 'respect NULs' '
 
-	git mailsplit -d3 -o. ../t5100/nul &&
-	cmp ../t5100/nul 001 &&
+	git mailsplit -d3 -o. ../t5100/nul-plain &&
+	cmp ../t5100/nul-plain 001 &&
 	(cat 001 | git mailinfo msg patch) &&
 	test 4 = $(wc -l < patch)
 
diff --git a/t/t5100/nul b/t/t5100/nul-plain
similarity index 100%
rename from t/t5100/nul
rename to t/t5100/nul-plain