abstract class PHPUnit_Framework_Constraint

abstract class PHPUnit_Framework_Constraint implements Countable, PHPUnit_Framework_SelfDescribing {

  /**
   * Evaluates the constraint for parameter $other
   *
   * If $returnResult is set to FALSE (the default), an exception is thrown
   * in case of a failure. NULL is returned otherwise.
   *
   * If $returnResult is TRUE, the result of the evaluation is returned as
   * a boolean value instead: TRUE in case of success, FALSE in case of a
   * failure.
   *
   * @param  mixed $other Value or object to evaluate.
   * @param  string $description Additional information about the test
   * @param  bool $returnResult Whether to return a result or throw an exception
   * @return mixed
   * @throws PHPUnit_Framework_ExpectationFailedException
   */
  public function evaluate($other, $description = '', $returnResult = FALSE) {
    $success = FALSE;
    if ($this
      ->matches($other)) {
      $success = TRUE;
    }
    if ($returnResult) {
      return $success;
    }
    if (!$success) {
      $this
        ->fail($other, $description);
    }
  }

  /**
   * Evaluates the constraint for parameter $other. Returns TRUE if the
   * constraint is met, FALSE otherwise.
   *
   * This method can be overridden to implement the evaluation algorithm.
   *
   * @param mixed $other Value or object to evaluate.
   * @return bool
   */
  protected function matches($other) {
    return FALSE;
  }

  /**
   * Counts the number of constraint elements.
   *
   * @return integer
   * @since  Method available since Release 3.4.0
   */
  public function count() {
    return 1;
  }

  /**
   * Throws an exception for the given compared value and test description
   *
   * @param  mixed $other Evaluated value or object.
   * @param  string $description Additional information about the test
   * @param  PHPUnit_Framework_ComparisonFailure $comparisonFailure
   * @throws PHPUnit_Framework_ExpectationFailedException
   */
  protected function fail($other, $description, PHPUnit_Framework_ComparisonFailure $comparisonFailure = NULL) {
    $failureDescription = sprintf('Failed asserting that %s.', $this
      ->failureDescription($other));
    $additionalFailureDescription = $this
      ->additionalFailureDescription($other);
    if ($additionalFailureDescription) {
      $failureDescription .= "\n" . $additionalFailureDescription;
    }
    if (!empty($description)) {
      $failureDescription = $description . "\n" . $failureDescription;
    }
    throw new PHPUnit_Framework_ExpectationFailedException($failureDescription, $comparisonFailure);
  }

  /**
   * Return additional failure description where needed
   *
   * The function can be overridden to provide additional failure
   * information like a diff
   *
   * @param  mixed $other Evaluated value or object.
   * @return string
   */
  protected function additionalFailureDescription($other) {
    return "";
  }

  /**
   * Returns the description of the failure
   *
   * The beginning of failure messages is "Failed asserting that" in most
   * cases. This method should return the second part of that sentence.
   *
   * To provide additional failure information additionalFailureDescription
   * can be used.
   *
   * @param  mixed $other Evaluated value or object.
   * @return string
   */
  protected function failureDescription($other) {
    return PHPUnit_Util_Type::export($other) . ' ' . $this
      ->toString();
  }

}