public function testPrePersist()
 {
     $this->assertNull($this->target->getCreatedAt());
     $this->assertNull($this->target->getUpdatedAt());
     $this->target->prePersist();
     $this->assertInstanceOf('\\DateTime', $this->target->getCreatedAt());
     $this->assertInstanceOf('\\DateTime', $this->target->getUpdatedAt());
     $expectedCreated = $this->target->getCreatedAt();
     $expectedUpdated = $this->target->getUpdatedAt();
     $this->target->prePersist();
     $this->assertSame($expectedCreated, $this->target->getCreatedAt());
     $this->assertGreaterThanOrEqual($expectedUpdated, $this->target->getUpdatedAt());
     $this->assertNotSame($expectedUpdated, $this->target->getUpdatedAt());
 }