diff --git a/tests/phpunit/tests/menu/wp-nav-menu.php b/tests/phpunit/tests/menu/wp-nav-menu.php
index a077766567..08f105be9a 100644
--- a/tests/phpunit/tests/menu/wp-nav-menu.php
+++ b/tests/phpunit/tests/menu/wp-nav-menu.php
@@ -7,11 +7,11 @@
  */
 class Tests_Menu_wpNavMenu extends WP_UnitTestCase {
 
-	static $menu_id        = 0;
-	static $lvl0_menu_item = 0;
-	static $lvl1_menu_item = 0;
-	static $lvl2_menu_item = 0;
-	static $lvl3_menu_item = 0;
+	private static $menu_id        = 0;
+	private static $lvl0_menu_item = 0;
+	private static $lvl1_menu_item = 0;
+	private static $lvl2_menu_item = 0;
+	private static $lvl3_menu_item = 0;
 
 	public static function set_up_before_class() {
 		parent::set_up_before_class();
diff --git a/tests/phpunit/tests/query/fieldsClause.php b/tests/phpunit/tests/query/fieldsClause.php
index 87f78a8719..28c040d79c 100644
--- a/tests/phpunit/tests/query/fieldsClause.php
+++ b/tests/phpunit/tests/query/fieldsClause.php
@@ -11,14 +11,14 @@ class Tests_Query_FieldsClause extends WP_UnitTestCase {
 	 *
 	 * @var int[]
 	 */
-	static $post_ids = array();
+	private static $post_ids = array();
 
 	/**
 	 * Page IDs.
 	 *
 	 * @var int[]
 	 */
-	static $page_ids = array();
+	private static $page_ids = array();
 
 	public static function wpSetUpBeforeClass( WP_UnitTest_Factory $factory ) {
 		// Register CPT for use with shared fixtures.