/**
*
*/
public function testCrawl()
{
$source = 'source';
$urls = [];
$Crawler = $this->getMockBuilder('\\Essence\\Crawler')->disableOriginalConstructor()->getMock();
$Crawler->expects($this->once())->method('crawl')->with($this->isEqual($source))->will($this->returnValue($urls));
$Essence = new Essence(['Crawler' => $Crawler]);
$this->assertEquals($urls, $Essence->crawl($source));
}