AdsUtilityRegistry::getInstance PHP Method

    public static function getInstance()
    {
        if (AdsUtilityRegistry::$instance === null) {
            AdsUtilityRegistry::$instance = new AdsUtilityRegistry();
        }
        return AdsUtilityRegistry::$instance;
    }

 /**
  * @covers AdsUtilityRegistry::addUtility
  * @covers AdsUtilityRegistry::popAllUtilities
  */
 public function testAddAndPopRegisteredUtilities()
 {
     AdsUtilityRegistry::getInstance()->addUtility('BatchJobHelper');
     AdsUtilityRegistry::getInstance()->addUtility('ReportDownloader/file');
     AdsUtilityRegistry::getInstance()->addUtility('ReportDownloader/string');
     $expected = array('BatchJobHelper' => 'BatchJobHelper', 'ReportDownloader/file' => 'ReportDownloader/file', 'ReportDownloader/string' => 'ReportDownloader/string');
     // First time, get all registered ads utilities.
     $this->assertEquals($expected, AdsUtilityRegistry::getInstance()->popAllUtilities());
     // Second time and later, get an empty list.
     $this->assertEquals(array(), AdsUtilityRegistry::getInstance()->popAllUtilities());
     $this->assertEquals(array(), AdsUtilityRegistry::getInstance()->popAllUtilities());
 }