/**
  * @param Collection $collection
  * @depends testFilter
  */
 public function testFilterReceivesKey(Collection $collection)
 {
     $actual = [];
     $collection->filter(function ($value, $key) use(&$actual) {
         $actual[$key] = $value;
         return true;
     });
     $this->assertSame($collection->toArray(), $actual);
 }