SparkPost\SparkPostResponse::withAddedHeader PHP Метод

    public function withAddedHeader($name, $value)
    {
        return $this->response->withAddedHeader($name, $value);
    }

 public function testWithAddedHeader()
 {
     $param = 'header';
     $param2 = 'value';
     $this->responseMock->shouldReceive('withAddedHeader')->andReturn($this->returnValue);
     $sparkpostResponse = new SparkPostResponse($this->responseMock);
     $this->assertEquals($this->responseMock->withAddedHeader($param, $param2), $sparkpostResponse->withAddedHeader($param, $param2));
 }