t6300: add a test for --ignore-case

The --ignore-case option was added by 3bb16a8bf2 (tag,
branch, for-each-ref: add --ignore-case for sorting and
filtering, 2016-12-04), but it was never tested. And indeed,
it does not work due to multiple bugs (which will be fixed
in subsequent patches).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t6300-for-each-ref.sh

@@ -795,4 +795,15 @@ test_expect_success ':remotename and :remoteref' '
 	)
 '
 
+test_expect_failure 'for-each-ref --ignore-case ignores case' '
+	>expect &&
+	git for-each-ref --format="%(refname)" refs/heads/MASTER >actual &&
+	test_cmp expect actual &&
+
+	echo refs/heads/master >expect &&
+	git for-each-ref --format="%(refname)" --ignore-case \
+		refs/heads/MASTER >actual &&
+	test_cmp expect actual
+'
+
 test_done