function testShouldFilterServiceCodesByCategory4()
 {
     $product = $this->newProduct(1);
     $product = new Elite_Vafdiagram_Model_Catalog_Product($product);
     $product->addServiceCode(123, array('category1' => 1, 'category2' => 1, 'category3' => 1, 'category4' => 1));
     $product->addServiceCode(456, array('category1' => 1, 'category2' => 1, 'category3' => 1, 'category4' => 2));
     $actual = $product->serviceCodes(array('category1' => 1, 'category2' => 1, 'category3' => 1, 'category4' => 2));
     $this->assertEquals(array(456), $actual, 'should filter service codes by category 4');
 }