public function testRegister()
{
$entity = new \stdClass();
$entity->test = 1;
$entityType = "Test";
$identifier = 42;
$this->assertNull($this->entityRegistry->retrieve($entityType, $identifier));
$this->entityRegistry->register($entityType, $identifier, $entity);
$this->assertEquals($entity, $this->entityRegistry->retrieve($entityType, $identifier));
$this->assertTrue($this->entityRegistry->remove($entityType, $identifier));
$this->assertNull($this->entityRegistry->retrieve($entityType, $identifier));
}