/**
  * Test getCertificateById().
  */
 public function testGetCertificateById()
 {
     $certificate1 = new Certificate();
     $certificate2 = new Certificate();
     $certificate3 = new Certificate();
     $certificate1->setId(1);
     $certificate2->setId(2);
     $certificate3->setId(3);
     $this->_builder->setCertificates(array($certificate1, $certificate2, $certificate3));
     $this->assertEquals($this->_builder->getCertificateById(1), $certificate1);
     $this->assertNull($this->_builder->getCertificateById(500));
 }