private function getSizes(DigitalOcean $digitalOcean)
 {
     foreach ($digitalOcean->sizes()->getAll()->sizes as $size) {
         $sizes[$size->id] = $size->name;
     }
     return $sizes;
 }
    public function testReturnsSizeInstance()
    {
        $digitalOcean = new DigitalOcean($this->getMockCredentials(), $this->getMockAdapter($this->never()));
        $sizes = $digitalOcean->sizes();

        $this->assertTrue(is_object($sizes));
        $this->assertInstanceOf('\\DigitalOcean\\Sizes\\Sizes', $sizes);
    }