public function testToArrayDateTime()
 {
     $object = new TestDateTime();
     $time = new DateTime();
     $object->setDateTimeConstant($time)->setDateTimeString($time)->setDateTimeStringWithSpace($time)->setEmptyDateTimeFormat($time);
     $result = $this->unitUnderTest->toArray($object);
     $this->assertCount(4, $result);
     $this->assertArrayHasKey('dateTimeConstant', $result);
     $this->assertArrayHasKey('dateTimeString', $result);
     $this->assertArrayHasKey('dateTimeStringWithSpace', $result);
     $this->assertArrayHasKey('emptyDateTimeFormat', $result);
     $this->assertEquals($time->format(DateTime::COOKIE), $result['dateTimeConstant']);
     $this->assertEquals($time->format('Y-m-d\\TH:i:sP'), $result['dateTimeString']);
     $this->assertEquals($time->format('D, d M y H:i:s O'), $result['dateTimeStringWithSpace']);
     $this->assertEquals($time->format(DateTime::ISO8601), $result['emptyDateTimeFormat']);
 }