AssetManager\Resolver\CollectionResolver::setAssetFilterManager PHP Method

    public function setAssetFilterManager(AssetFilterManager $filterManager)
    {
        $this->filterManager = $filterManager;
    }

 public function testSuccessResolve()
 {
     $callbackInvocationCount = 0;
     $callback = function () use(&$callbackInvocationCount) {
         $asset1 = new Asset\StringAsset('bacon');
         $asset2 = new Asset\StringAsset('eggs');
         $asset3 = new Asset\StringAsset('Mud');
         $asset1->mimetype = 'text/plain';
         $asset2->mimetype = 'text/plain';
         $asset3->mimetype = 'text/plain';
         $callbackInvocationCount += 1;
         $assetName = "asset{$callbackInvocationCount}";
         return ${$assetName};
     };
     $aggregateResolver = $this->getMock('AssetManager\\Resolver\\ResolverInterface');
     $aggregateResolver->expects($this->exactly(3))->method('resolve')->will($this->returnCallback($callback));
     $resolver = new CollectionResolver(array('myCollection' => array('bacon', 'eggs', 'mud')));
     $mimeResolver = new MimeResolver();
     $assetFilterManager = new AssetFilterManager();
     $assetFilterManager->setMimeResolver($mimeResolver);
     $resolver->setAggregateResolver($aggregateResolver);
     $resolver->setAssetFilterManager($assetFilterManager);
     $collectionResolved = $resolver->resolve('myCollection');
     $this->assertEquals($collectionResolved->mimetype, 'text/plain');
     $this->assertTrue($collectionResolved instanceof Asset\AssetCollection);
 }