/**
  * Implements corresponding isValidXX logic.
  *
  * @param string $context   Please see corresponding isValidXX description.
  * @param string $input     Please see corresponding isValidXX description.
  * @param int    $format    Please see corresponding isValidXX description.
  * @param bool   $allowNull Please see corresponding isValidXX description.
  *
  * @return does not return a value.
  * @throws ValidationException thrown if input is invalid.
  * @throws IntrusionException thrown if intrusion is detected.
  */
 private function _assertValidDate($context, $input, $format, $allowNull)
 {
     $dvr = new DateValidationRule('DateValidator', $this->_encoder, $format);
     $dvr->setAllowNull($allowNull);
     $dvr->assertValid($context, $input);
     return null;
 }
 /**
  * constructor sets a sane default date format string ('Y-m-d')
  */
 function testDateVR_construct_format()
 {
     $dvr = new DateValidationRule('DateValidator');
     $this->assertTrue($dvr->getValid('testDateVR_construct_format', '1970-01-31')->format('Y-m-d') == '1970-01-31');
 }