Validator Composability

[offirgolan]

Easily compose complicated validations by using this this.test to validate
against pre-existing validators.

validate(value, options, ...args) {
  let result = this.test('presence', value, { presence: true }, ...args);

  if (!result.isValid) {
    return result.message;
  }

  result = this.test('number', value, { integer: true }, ...args);

  // You can easily override the error message by returning your own.
  if (!result.isValid) {
      return 'This value must be an integer!';
    }

  // Add custom logic...

  return true;
}

Tasks:

• Added test case(s)
• Updated documentation