diff --git a/dir.c b/dir.c
index 7c4b45e30e..da93374f0c 100644
--- a/dir.c
+++ b/dir.c
@@ -2297,7 +2297,8 @@ int read_directory(struct dir_struct *dir, struct index_state *istate,
 				 dir->untracked->gitignore_invalidated,
 				 dir->untracked->dir_invalidated,
 				 dir->untracked->dir_opened);
-		if (dir->untracked == istate->untracked &&
+		if (getenv("GIT_TEST_UNTRACKED_CACHE") &&
+			dir->untracked == istate->untracked &&
 		    (dir->untracked->dir_opened ||
 		     dir->untracked->gitignore_invalidated ||
 		     dir->untracked->dir_invalidated))
diff --git a/t/t7063-status-untracked-cache.sh b/t/t7063-status-untracked-cache.sh
index e5fb892f95..6ef520e823 100755
--- a/t/t7063-status-untracked-cache.sh
+++ b/t/t7063-status-untracked-cache.sh
@@ -14,6 +14,9 @@ test_description='test untracked cache'
 # See <20160803174522.5571-1-pclouds@gmail.com> if you want to know
 # more.
 
+GIT_TEST_UNTRACKED_CACHE=true
+export GIT_TEST_UNTRACKED_CACHE
+
 sync_mtime () {
 	find . -type d -ls >/dev/null
 }