public function testSortByPriority()
 {
     $subclass1 = $this->subclassCollection->get(1);
     $subclass2 = $this->subclassCollection->get(2);
     $this->subclassCollection->sortByPriority();
     $this->assertEquals(array(2 => $subclass2, 1 => $subclass1), $this->subclassCollection->toArray());
 }