Bluz\Validator\Rule\Date::validate PHP Method

    public function validate($input) : bool
    {
        if ($input instanceof DateTime) {
            return true;
        } elseif (!is_string($input)) {
            return false;
        } elseif (is_null($this->format)) {
            return false !== strtotime($input);
        }
        $dateFromFormat = DateTime::createFromFormat($this->format, $input);
        return $dateFromFormat && $input === date($this->format, $dateFromFormat->getTimestamp());
    }

 /**
  * @dataProvider providerForFail
  */
 public function testInvalidateDateShouldFail($format, $date)
 {
     $validator = new Date($format);
     $this->assertFalse($validator->validate($date));
     $this->assertNotEmpty($validator->__toString());
 }