public function testHtmlGraph()
 {
     $profile = new \Twig_Profiler_Profile();
     $template1 = new \Twig_Profiler_Profile('template1', \Twig_Profiler_Profile::TEMPLATE, 'template1');
     $profile->addProfile($template1);
     $profile->enter();
     $template1->enter();
     usleep(10000);
     $template1->leave();
     $profile->leave();
     $collector = new HandlebarsDataCollector($profile);
     $this->assertContains('template1', (string) $collector->getHtmlCallGraph());
 }