public async void AddAsync_NewTaskAdded()
        {
            var newTask     = _fixture.Create <TaskDomain>();
            var newGuid     = _fixture.Create <Guid>();
            var newDateTime = _fixture.Create <DateTime>();

            var dbTask = new DbTask
            {
                Id          = newGuid,
                AddedDate   = newDateTime,
                State       = newTask.State,
                DueDate     = newTask.DueDate,
                Priority    = newTask.Priority,
                Description = newTask.Description
            };

            _guidFactory.Setup(x => x.Create()).Returns(newGuid).Verifiable();
            _dateTimeProvider.Setup(x => x.Now).Returns(newDateTime).Verifiable();
            _dbRepository
            .Setup(x => x.Add(It.IsAny <DbTask>()))
            .Callback <DbTask>(x => x.Should().BeEquivalentTo(dbTask))
            .Verifiable();

            await _tasksRepository.AddAsync(newTask);

            _dateTimeProvider.VerifyAll();
            _dbRepository.VerifyAll();
            _guidFactory.VerifyAll();
        }