/** @test */
 public function setOverwritesInstances()
 {
     $listIdentifier = 'testListIdentifier';
     $dataBackenMock = $this->getMock('Tx_PtExtlist_Domain_DataBackend_Typo3DataBackend_Typo3DataBackend', array('getListIdentifier'), array(), '', FALSE);
     $dataBackenMock->expects($this->any())->method('getListIdentifier')->will($this->returnValue($listIdentifier));
     $instancesContainer = new Tx_PtExtlist_Domain_DataBackend_DataBackendInstancesContainer();
     $instancesContainer->add($dataBackenMock);
     $this->assertEquals($dataBackenMock, $instancesContainer->get($listIdentifier));
     $dataBackenMock2 = $this->getMock('Tx_PtExtlist_Domain_DataBackend_Typo3DataBackend_Typo3DataBackend', array('getListIdentifier'), array(), '', FALSE);
     $dataBackenMock2->expects($this->any())->method('getListIdentifier')->will($this->returnValue($listIdentifier));
     $instancesContainer->set($dataBackenMock2);
     $this->assertEquals($dataBackenMock2, $instancesContainer->get($listIdentifier));
 }