credential: let helpers tell us to quit

diff --git a/t/t7800-difftool.sh b/t/t7800-difftool.sh
index 5a193c500d282cc2b13e8de6e128229585897a16..dc30a514bf681dde44dea32e671632ef6f0a47a7 100755 (executable)
--- a/t/t7800-difftool.sh
+++ b/t/t7800-difftool.sh
@@ -58,7 +58,7 @@ test_expect_success PERL 'custom tool commands override built-ins' '
 
 test_expect_success PERL 'difftool ignores bad --tool values' '
        : >expect &&
-       test_expect_code 1 \
+       test_must_fail \
                git difftool --no-prompt --tool=bad-tool branch >actual &&
        test_cmp expect actual
 '