diff --git a/bin/install-wp-tests.sh b/bin/install-wp-tests.sh
old mode 100755
new mode 100644
index c6f53dc..88f2a57
--- a/bin/install-wp-tests.sh
+++ b/bin/install-wp-tests.sh
@@ -54,6 +54,7 @@ fi
 set -ex
 
 install_wp() {
+	rm -rf $WP_CORE_DIR
 
 	if [ -d $WP_CORE_DIR ]; then
 		return;