t2200: check that "add -u" limits itself to subdirectory

This behavior is due to change in the future, but let's test
it anyway. That helps make sure we do not accidentally
switch the behavior too soon while we are working in the
area, and it means that we can easily verify the change when
we do make it.

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

t/t2200-add-update.sh

@@ -80,6 +80,22 @@ test_expect_success 'change gets noticed' '
 
 '
 
+# Note that this is scheduled to change in Git 2.0, when
+# "git add -u" will become full-tree by default.
+test_expect_success 'non-limited update in subdir leaves root alone' '
+	(
+		cd dir1 &&
+		echo even more >>sub2 &&
+		git add -u
+	) &&
+	cat >expect <<-\EOF &&
+	check
+	top
+	EOF
+	git diff-files --name-only >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success SYMLINKS 'replace a file with a symlink' '
 
 	rm foo &&