public async Task CreateAsync_Should_Add_New_Entity_To_Database() { //Arrange var createTodoListModel = Builder <CreateTodoListModel> .CreateNew().Build(); var todoList = Mapper.Map <TodoList>(createTodoListModel); todoList.Id = Guid.NewGuid(); TodoListRepository.AddAsync(Arg.Any <TodoList>()).Returns(todoList); //Act var result = await _sut.CreateAsync(createTodoListModel); //Assert result.Id.Should().Be(todoList.Id); await TodoListRepository.Received().AddAsync(Arg.Any <TodoList>()); }