submodule: don't rely on overlayed config when setting diffopts

diff --git a/t/t5516-fetch-push.sh b/t/t5516-fetch-push.sh
index 0fc5a7c596b5d5e01ecb43f81d3d6eaafe611b7b..177897ea0b1e00cc4ec0f0e43510411ab19f1681 100755 (executable)
--- a/t/t5516-fetch-push.sh
+++ b/t/t5516-fetch-push.sh
@@ -1098,7 +1098,8 @@ test_expect_success 'fetch exact SHA1' '
                test_must_fail git cat-file -t $the_commit &&
 
                # fetching the hidden object should fail by default
-               test_must_fail git fetch -v ../testrepo $the_commit:refs/heads/copy &&
+               test_must_fail git fetch -v ../testrepo $the_commit:refs/heads/copy 2>err &&
+               test_i18ngrep "Server does not allow request for unadvertised object" err &&
                test_must_fail git rev-parse --verify refs/heads/copy &&
 
                # the server side can allow it to succeed