createMock(\Magento\Framework\Serialize\Serializer\Json::class); $serializer->expects($this->any()) ->method('serialize') ->willReturnCallback( function ($value) { return json_encode($value); } ); $serializer->expects($this->any()) ->method('unserialize') ->willReturnCallback( function ($value) { return json_decode($value, true); } ); $this->model = $objectManager->getObject( \Magento\UrlRewrite\Service\V1\Data\UrlRewrite::class, [ 'data' => [], 'serializer' => $serializer, ] ); } public function testSetAndGetMetadata() { $testData = [1, 2, 3]; $this->model->setMetadata($testData); $this->assertEquals($testData, $this->model->getMetadata()); } }