public function testHead()
 {
     $request = new Request('http://httpbin.org/', self::ADAPTER);
     $this->assertNotEmpty($request->head()->getHeaders()->all());
 }
 public function testStatusCode()
 {
     $request = new Request('http://httpbin.org/status/418', self::ADAPTER);
     $this->assertEquals(418, $request->get()->getStatusCode());
 }