public function managerThrowsExceptionOnCacheRegistrationWithAlreadyExistingIdentifier()
{
$cache1 = $this->getMockBuilder(Cache\Frontend\AbstractFrontend::class)->disableOriginalConstructor()->getMock();
$cache1->expects($this->atLeastOnce())->method('getIdentifier')->will($this->returnValue('test'));
$cache2 = $this->getMockBuilder(Cache\Frontend\AbstractFrontend::class)->disableOriginalConstructor()->getMock();
$cache2->expects($this->atLeastOnce())->method('getIdentifier')->will($this->returnValue('test'));
$this->cacheManager->registerCache($cache1);
$this->cacheManager->registerCache($cache2);
}