public async Task On_GetAllTodos_Should_Return_All_Todos()
        {
            // Given:
            var todos = new List <Todo>()
            {
                new Todo()
                {
                    Id        = 0,
                    Name      = "Water plants",
                    Completed = false
                },
                new Todo()
                {
                    Id        = 1,
                    Name      = "Wash dishes",
                    Completed = true
                }
            };

            // And:
            var queryRepository = new Mock <ITodoQueryRepository>();

            queryRepository
            .Setup(r => r.GetAllTodosAsync())
            .ReturnsAsync(todos);

            // And:
            var sut = new DefaultTodoService(null, queryRepository.Object);

            // When:
            var result = await sut.GetAllTodosAsync();

            // Then:
            Assert.Equal(2, result.Count);
        }
        public async Task On_GetAllTodos_Should_Throw_FailedToGetAllTodosException_When_Exception_Received()
        {
            // Given:
            var queryRepository = new Mock <ITodoQueryRepository>();

            queryRepository
            .Setup(r => r.GetAllTodosAsync())
            .ThrowsAsync(new NullReferenceException("Problems with database!"));

            // And:
            var sut = new DefaultTodoService(null, queryRepository.Object);

            // When:
            var func = new Func <Task>(async() => { await sut.GetAllTodosAsync(); });

            // Then:
            var result = await Assert.ThrowsAsync <FailedToGetAllTodosException>(func);

            Assert.Equal("Problems with database!", result.Message);
        }