diff --git a/tests/phpunit/tests/image/intermediate_size.php b/tests/phpunit/tests/image/intermediate_size.php
index 0d218172f8..d613b9d4d2 100644
--- a/tests/phpunit/tests/image/intermediate_size.php
+++ b/tests/phpunit/tests/image/intermediate_size.php
@@ -5,6 +5,8 @@
  * @group upload
  */
 class Tests_Image_Intermediate_Size extends WP_UnitTestCase {
+	protected $ids = array();
+
 	function tearDown() {
 		$this->remove_added_uploads();
 		parent::tearDown();
diff --git a/tests/phpunit/tests/post/attachments.php b/tests/phpunit/tests/post/attachments.php
index 7459c6ae4c..498f27652b 100644
--- a/tests/phpunit/tests/post/attachments.php
+++ b/tests/phpunit/tests/post/attachments.php
@@ -6,6 +6,7 @@
  * @group upload
  */
 class Tests_Post_Attachments extends WP_UnitTestCase {
+	protected $ids = array();
 
 	function tearDown() {
 		// Remove all uploads.
diff --git a/tests/phpunit/tests/post/wpUniquePostSlug.php b/tests/phpunit/tests/post/wpUniquePostSlug.php
index 690fc3ed48..354997e462 100644
--- a/tests/phpunit/tests/post/wpUniquePostSlug.php
+++ b/tests/phpunit/tests/post/wpUniquePostSlug.php
@@ -4,6 +4,8 @@
  * @group post
  */
 class Tests_Post_WpUniquePostSlug extends WP_UnitTestCase {
+	protected $post_ids = array();
+
 	/**
 	 * @ticket 21013
 	 */