public function seeResponseIsJson()
    {
        $responseContent = $this->connectionModule->_getResponseContent();
        \PHPUnit\Framework\Assert::assertNotEquals('', $responseContent, 'response is empty');
        json_decode($responseContent);
        $errorCode = json_last_error();
        $errorMessage = json_last_error_msg();
        \PHPUnit\Framework\Assert::assertEquals(
            JSON_ERROR_NONE,
            $errorCode,
            sprintf(
                "Invalid json: %s. System message: %s.",
                $responseContent,
                $errorMessage
            )
        );
    }