AssetManagerTest\Service\AssetFilterManagerTest::testFiltersAreInstantiatedOnce PHP Method

    public function testFiltersAreInstantiatedOnce()
    {
        $assetFilterManager = new AssetFilterManager(array('test/path.test' => array(array('filter' => 'CustomFilter'))));
        $filterInstance = null;
        $asset = $this->getMock(AssetInterface::class);
        $asset->expects($this->any())->method('ensureFilter')->with($this->callback(function (FilterInterface $filter) use(&$filterInstance) {
            if ($filterInstance === null) {
                $filterInstance = $filter;
            }
            return $filter === $filterInstance;
        }));
        $assetFilterManager->setFilters('test/path.test', $asset);
        $assetFilterManager->setFilters('test/path.test', $asset);
    }