public async Task UpdateAsync_Should_Throw_Exception_If_List_Does_Not_Exist_Anymore() { // Arrange var updateTodoItem = Builder <UpdateTodoItemModel> .CreateNew().Build(); _todoListRepository.GetFirstAsync(Arg.Any <Expression <Func <TodoList, bool> > >()).ReturnsNull(); // Act Func <Task> callCreateAsync = async() => await _sut.UpdateAsync(Guid.NewGuid(), updateTodoItem); // Assert callCreateAsync.Should().Throw <NotFoundException>().WithMessage("List does not exist anymore"); await _todoListRepository.Received().GetFirstAsync(Arg.Any <Expression <Func <TodoList, bool> > >()); }