public function testMerge()
 {
     $this->collection->add($this->target1);
     $this->collection->merge(array($this->target2, $this->target3));
     $this->assertSame(array('target1' => $this->target1, 'target2' => $this->target2, 'target3' => $this->target3), $this->collection->toArray());
 }