Symfony\Component\DomCrawler\Tests\CrawlerTest::testFilterXPath PHP Method

    public function testFilterXPath()
    {
        $crawler = $this->createTestCrawler();
        $this->assertNotSame($crawler, $crawler->filterXPath('//li'), '->filterXPath() returns a new instance of a crawler');
        $this->assertInstanceOf('Symfony\\Component\\DomCrawler\\Crawler', $crawler, '->filterXPath() returns a new instance of a crawler');

        $crawler = $this->createTestCrawler()->filterXPath('//ul');
        $this->assertCount(6, $crawler->filterXPath('//li'), '->filterXPath() filters the node list with the XPath expression');

        $crawler = $this->createTestCrawler();
        $this->assertCount(3, $crawler->filterXPath('//body')->filterXPath('//button')->parents(), '->filterXpath() preserves parents when chained');
    }