public void ShouldNotThrowExceptionWhenValid()
            {
                IAction action = new PostbackAction()
                {
                    Data  = "PostbackData",
                    Label = "PostbackLabel"
                };

                action.Validate();
            }
            public void ShouldThrowExceptionWhenTextIsNull()
            {
                IAction action = new PostbackAction()
                {
                    Label = "PostbackLabel"
                };

                ExceptionAssert.Throws <InvalidOperationException>("The data cannot be null.", () =>
                {
                    action.Validate();
                });
            }
            public void ShouldThrowExceptionWhenLabelIsNull()
            {
                IAction action = new PostbackAction()
                {
                    Data = "PostbackData"
                };

                ExceptionAssert.Throws <InvalidOperationException>("The label cannot be null.", () =>
                {
                    action.Validate();
                });
            }