restore: add test for deleted ita files

`git restore --staged` uses the same machinery as `git checkout HEAD`,
so there should be a similar test case for "restore" as the existing
test case for "checkout" with deleted ita files.

Helped-by: Jeff King <[email protected]>
Signed-off-by: Varun Naik <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: varuncnaik

t/t2070-restore.sh

@@ -95,4 +95,15 @@ test_expect_success 'restore --ignore-unmerged ignores unmerged entries' '
 	)
 '
 
+test_expect_success 'restore --staged adds deleted intent-to-add file back to index' '
+	echo "nonempty" >nonempty &&
+	>empty &&
+	git add nonempty empty &&
+	git commit -m "create files to be deleted" &&
+	git rm --cached nonempty empty &&
+	git add -N nonempty empty &&
+	git restore --staged nonempty empty &&
+	git diff --cached --exit-code
+'
+
 test_done