public function testInsertDuplicateSnapshot()
 {
     $this->testSubject->appendSnapshotEvent("test", new GenericDomainEventMessage("id1", 1, new \stdClass()));
     try {
         $this->testSubject->appendSnapshotEvent("test", new GenericDomainEventMessage("id1", 1, new \stdClass()));
         $this->fail("Expected concurrency exception");
     } catch (ConcurrencyException $ex) {
         $this->assertRegExp('/SnapshotEvent/', $ex->getMessage());
     }
 }