Added test for nullable filters.

Author: Kyle Spraggs

tests/AssetManagerTest/Service/AssetFilterManagerTest.php

@@ -17,6 +17,21 @@ public function setUp()
         require_once __DIR__ . '/../../_files/CustomFilter.php';
     }
 
+    public function testNulledValuesAreSkipped()
+    {
+        $assetFilterManager = new AssetFilterManager(array(
+	    'test/path.test' => array(
+	        'null_filters' => null
+	    )
+        ));
+	
+	    $asset = new StringAsset('Herp Derp');
+
+    	$assetFilterManager->setFilters('test/path.test', $asset);
+
+	    $this->assertEquals('called', $asset->dump());
+    }
+
     public function testensureByService()
     {
         $assetFilterManager = new AssetFilterManager(array(