only in patch2:
unchanged:
--- a/core/tests/Drupal/Tests/Core/Config/Entity/ConfigEntityBaseUnitTest.php
+++ b/core/tests/Drupal/Tests/Core/Config/Entity/ConfigEntityBaseUnitTest.php
@@ -635,6 +635,9 @@ public function testToArraySchemaException() {
     $this->entityType->expects($this->any())
       ->method('getPropertiesToExport')
       ->willReturn(NULL);
+    $this->entityType->expects($this->any())
+      ->method('getClass')
+      ->willReturn("Mock_ConfigEntityTypeInterface_[^']*");
     $this->expectException(SchemaIncompleteException::class);
     $this->expectExceptionMessageRegExp("/Entity type 'Mock_ConfigEntityTypeInterface_[^']*' is missing 'config_export' definition in its annotation/");
     $this->entity->toArray();