New in .NET 8.0 [18]: A time lapse with its own FakeTimeProvider

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The previous blog post about the new features in .NET 8.0 discussed the newly introduced System.TimeProvider class and the FakeTimeProvider from Microsoft based on it in the NuGet package Microsoft.Extensions.TimeProvider.Testing.

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But you can also write a FakeTimeProvider yourself. In the following listing, the class ITVisionsFakeTimeProvider implements its own provider based on the abstract base class System.TimeProvider. This ITVisionsFakeTimeProvider always returns the same time that was passed in the constructor and can be presented using Advance().

In addition to Microsoft’s implementation, the class offers an adjustable time lapse. For example, by specifying 3 as time lapse in the constructor, waiting only takes two seconds instead of six:

ITVisionsFakeTimeProvider ftp =
new(DateTime.Parse(“14.11.2023 18:00:00”), 3);
await ftp.Delay(new TimeSpan(0, 0, 6));
// oder
await Task.Delay(new TimeSpan(0, 0, 5), ftp);

The time lapse also works on timers. While this timer goes off every three seconds

TimeProvider.System.CreateTimer
((x) => Callback(TimeProvider.System),
null,
new TimeSpan(0, 0, 3),
new TimeSpan(0, 0, 3));

Here, due to time lapse 3, the trigger occurs every second:

ftp.CreateTimer((x) => Callback(ftp),
null,
new TimeSpan(0, 0, 3),
new TimeSpan(0, 0, 3));

Here is a code example using the ITVisionsFakeTimeProvider:

///

/// This FakeTimeProvider always returns the same time /// that was passed in the constructor. The timer can be advanced /// using Advance(). There is a time lapse for the timer. ///

class ITVisionsFakeTimeProvider : TimeProvider
{
private readonly DateTimeOffset _date;
int _timeLapse = 1;
public ITVisionsFakeTimeProvider(DateTimeOffset date,
int timeLapse = 1)
{
_date = date;
_timeLapse = timeLapse;
}
public override DateTimeOffset GetUtcNow()
{
return _date;
}

///

/// Introduce time ///

public void Advance(TimeSpan timeSpan)
{
_date.Add(timeSpan);
}

///

/// Timer with time lapse ///

public override ITimer CreateTimer(TimerCallback callback,
object state,
TimeSpan dueTime,
TimeSpan period)
{
return base.CreateTimer(callback, state,
new TimeSpan((long)(dueTime.Ticks / _timeLapse)),
new TimeSpan((long)(period.Ticks / _timeLapse)));
}

}

(Image: Dmytro Vikarchuk/Shutterstock)

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(rme)

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