message: added is default value test
diff: @@ -3,4 +3,5 @@ import validate from './../../src/rules/is';
  test('checks if the value matches another', () => {
  expect(validate(1, ['1'])).toBe(false);
  expect(validate(1, [1])).toBe(true);
  + expect(validate(1)).toBe(false);
  });
  