t3001: test ls-files -o ignored/dir

When you have "t" directory that is marked as ignored in the top-level
.gitignore file (or $GIT_DIR/info/exclude), running

    $ git ls-files -o --exclude-standard

from the top-level correctly excludes files in "t" directory, but
any of the following:

    $ git ls-files -o --exclude-standard t/
    $ cd t && git ls-files -o --exclude-standard

would show untracked files in that directory.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t3001-ls-files-others-exclude.sh

@@ -153,4 +153,43 @@ test_expect_success 'negated exclude matches can override previous ones' '
 	grep "^a.1" output
 '
 
+test_expect_success 'subdirectory ignore (setup)' '
+	mkdir -p top/l1/l2 &&
+	(
+		cd top &&
+		git init &&
+		echo /.gitignore >.gitignore &&
+		echo l1 >>.gitignore &&
+		echo l2 >l1/.gitignore &&
+		>l1/l2/l1
+	)
+'
+
+test_expect_success 'subdirectory ignore (toplevel)' '
+	(
+		cd top &&
+		git ls-files -o --exclude-standard
+	) >actual &&
+	>expect &&
+	test_cmp expect actual
+'
+
+test_expect_success 'subdirectory ignore (l1/l2)' '
+	(
+		cd top/l1/l2 &&
+		git ls-files -o --exclude-standard
+	) >actual &&
+	>expect &&
+	test_cmp expect actual
+'
+
+test_expect_failure 'subdirectory ignore (l1)' '
+	(
+		cd top/l1 &&
+		git ls-files -o --exclude-standard
+	) >actual &&
+	>expect &&
+	test_cmp expect actual
+'
+
 test_done