public void Delete_não_deve_perguntar_para_excluir_um_tópico_inexistente()
        {
            //Arrange
            var guidBase = Guid.NewGuid();
            var mock = new Mock<ITopicRepository>();
            mock.
                Setup(m => m.ReadById(guidBase)).
                Returns((Topic) null);
            var controller = new TopicController(mock.Object);

            //Act
            var result = (RedirectToRouteResult) controller.Delete(guidBase);

            //Assert
            Assert.AreEqual("Index", result.RouteValues["action"]);
        }
        public void Delete_deve_perguntar_para_excluir_um_tópico_válido()
        {
            //Arrange
            var guidBase = Guid.NewGuid();
            var topic = new Topic() { Id = guidBase, Value = "gradiente" };
            var mock = new Mock<ITopicRepository>();
            mock.
                Setup(m => m.ReadById(guidBase)).
                Returns(topic);
            var controller = new TopicController(mock.Object);

            //Act
            var result = (ViewResult)controller.Delete(topic.Id);

            //Assert
            Assert.AreEqual("", result.ViewName);
        }