Doctrine\OXM\Types\TimeType::convertToXmlValue PHP Метод

    public function convertToXmlValue($value)
    {
        return $value !== null ? $value->format(static::FORMAT) : null;
    }

 public function testTimeConvertsToDatabaseValue()
 {
     $this->assertInternalType('string', $this->_type->convertToXmlValue(new \DateTime()));
 }