diff --git a/t/helper/test-dump-cache-tree.c b/t/helper/test-dump-cache-tree.c
index 44f3290258..7af116d49e 100644
--- a/t/helper/test-dump-cache-tree.c
+++ b/t/helper/test-dump-cache-tree.c
@@ -58,6 +58,7 @@ int cmd_main(int ac, const char **av)
 {
 	struct index_state istate;
 	struct cache_tree *another = cache_tree();
+	setup_git_directory();
 	if (read_cache() < 0)
 		die("unable to read index file");
 	istate = the_index;
diff --git a/t/helper/test-scrap-cache-tree.c b/t/helper/test-scrap-cache-tree.c
index 5b2fd09908..27fe0405b8 100644
--- a/t/helper/test-scrap-cache-tree.c
+++ b/t/helper/test-scrap-cache-tree.c
@@ -7,6 +7,7 @@ static struct lock_file index_lock;
 
 int cmd_main(int ac, const char **av)
 {
+	setup_git_directory();
 	hold_locked_index(&index_lock, 1);
 	if (read_cache() < 0)
 		die("unable to read index file");