code: function validate() {
    const target = this._obj;
  
    isValidation(target);
    this.assert(_.has(target, 'error') && null === target.error,
        '#{this} should validate but does not because '+getErrorMessages(target),
        '#{this} should not validate but it does'
    );
  }
docs: Assert that target validates correctly
  @example
  expect(target).should.[not].validate
  target.should.[not].validate