diff --git a/tests/phpunit/includes/testcase-rest-api.php b/tests/phpunit/includes/testcase-rest-api.php
index c857e0e392..5430d269d1 100644
--- a/tests/phpunit/includes/testcase-rest-api.php
+++ b/tests/phpunit/includes/testcase-rest-api.php
@@ -7,7 +7,7 @@ abstract class WP_Test_REST_TestCase extends WP_UnitTestCase {
 			$response = $response->as_error();
 		}
 
-		$this->assertInstanceOf( 'WP_Error', $response );
+		$this->assertWPError( $response );
 		$this->assertEquals( $code, $response->get_error_code() );
 
 		if ( null !== $status ) {
diff --git a/tests/phpunit/tests/date/query.php b/tests/phpunit/tests/date/query.php
index 0445fd819f..fe31577e04 100644
--- a/tests/phpunit/tests/date/query.php
+++ b/tests/phpunit/tests/date/query.php
@@ -9,6 +9,9 @@
  * @group date
  */
 class Tests_WP_Date_Query extends WP_UnitTestCase {
+	/**
+	 * @var WP_Date_Query $q
+	 */
 	public $q;
 
 	public function setUp() {
diff --git a/tests/phpunit/tests/rest-api/rest-autosaves-controller.php b/tests/phpunit/tests/rest-api/rest-autosaves-controller.php
index 609fbb73c9..0984bd3f83 100644
--- a/tests/phpunit/tests/rest-api/rest-autosaves-controller.php
+++ b/tests/phpunit/tests/rest-api/rest-autosaves-controller.php
@@ -38,7 +38,7 @@ class WP_Test_REST_Autosaves_Controller extends WP_Test_REST_Post_Type_Controlle
 	}
 
 	protected function check_create_autosave_response( $response ) {
-		$this->assertNotInstanceOf( 'WP_Error', $response );
+		$this->assertNotWPError( $response );
 		$response = rest_ensure_response( $response );
 		$data     = $response->get_data();