tests: use 'test_must_be_empty' instead of 'test_cmp /dev/null <out>'

diff --git a/t/t5541-http-push-smart.sh b/t/t5541-http-push-smart.sh
index a2af693068fa455838c97df1fefe38bd630ceb2e..4319ef6ec777c1d9797294adba08bba91ab40808 100755 (executable)
--- a/t/t5541-http-push-smart.sh
+++ b/t/t5541-http-push-smart.sh
@@ -226,7 +226,7 @@ test_expect_success TTY 'push --quiet silences status and progress' '
        cd "$ROOT_PATH"/test_repo_clone &&
        test_commit quiet &&
        test_terminal git push --quiet >output 2>&1 &&
-       test_cmp /dev/null output
+       test_must_be_empty output
 '
 
 test_expect_success TTY 'push --no-progress silences progress but not status' '