How to use custom DateTime.now in integration test for ASP.NET Core Web API?

Question

I have an integration test in my project that should use DateTime.Now .

This is my method:

public static ErrorResult CheckAvailabiliteOfOrderDeliveryInCurrentTime(string openingTime,string closingTime)
{
    var currentTimeString = System.DateTime.Now.ToString("HH:mm:ss"); 

    if (DateTime.Parse(openingTime + ":00") > DateTime.Parse(closingTime + ":00"))
    {
        if ((DateTime.Parse(currentTimeString) <= DateTime.Parse("23:59:00") && 
             DateTime.Parse(currentTimeString) > DateTime.Parse(openingTime + ":00")) || 
            (DateTime.Parse(currentTimeString) < DateTime.Parse(closingTime + ":00") && 
             DateTime.Parse(currentTimeString) >= DateTime.Parse("00:00:00")))
        {
            return ErrorResult.None;
        }
        else
        {
            return ErrorResult.OutOfDeliveryTime;
        }
    }
    else
    {
        if (DateTime.Parse(currentTimeString) < DateTime.Parse(closingTime + ":00") && 
            DateTime.Parse(currentTimeString) > DateTime.Parse(openingTime + ":00"))
        {
            return ErrorResult.None;
        }
        else
        {
            return ErrorResult.OutOfDeliveryTime;
        }
    }
}

My handler method that call this method:

public async Task<OrderDto> Handle(CreateOrderCommand request, CancellationToken cancellationToken)
{
    var validator = new CreateOrderCommandValidator();
    var result = await validator.ValidateAsync(request, cancellationToken).ConfigureAwait(false);

    if (!result.IsValid) 
         throw new ValidationException(result);

    var foodBusiness = await _context.FoodBusinesses.FindAsync(Guid.Parse(request.FoodBusinessId));

    if (foodBusiness == null)
        throw new NotFoundException(nameof(FoodBusiness), request.FoodBusinessId);

    if (request.Type == OrderTypes.Delivery)
    {   
        var isOutdeliveryTime = DateTimeHelpers.CheckAvailabiliteOfOrderDeliveryInCurrentTime(foodBusiness.OpeningTime, foodBusiness.ClosingTime);

        if (isOutdeliveryTime == ErrorResult.OutOfDeliveryTime)
        {
            var newOrder = new OrderDto();
            newOrder.errorDeliveryTimeAvailabilite = ErrorResult.OutOfDeliveryTime;

            return _mapper.Map<OrderDto>(newOrder);
        }
        else
        {
            var newOrder = await ExecuteOrderOperations(request, cancellationToken, foodBusiness);
            return _mapper.Map<OrderDto>(newOrder);
        }
    }
    else
    {
        var newOrder = await ExecuteOrderOperations(request, cancellationToken, foodBusiness);
        return _mapper.Map<OrderDto>(newOrder);
    }
}

By default application us using System.DateTime.Now , but in the integration test, I need to use my own DateTime.Now - is there any solution for this? Thanks

Answer 1

Your opinions are:

1. Refactor the code to be testable. Eg create a ISystemClock and have your unit test use a mock.
2. Purchase Visual Studio Enterprise and use Microsoft Fakes or some other third-party solution.