Unit testing retry policies with timeout intervals

Currently I don’t see a way to unit test a retry policy if you use the time-based retry policy.

Let’s say you use the following approach, and this code below is part of your method that does a few more things than executing the policy itself.

Some code here…

Policy
  .Handle<DivideByZeroException>()
  .WaitAndRetry(new[]
  {
    TimeSpan.FromSeconds(30),
    TimeSpan.FromSeconds(60),
    TimeSpan.FromSeconds(120)
  }, (exception, timeSpan) => {
    // do something    
  }); 

Some code here…

How would I test what happens after we have re-tried 3 times? I don’t want to wait more than one minute in my tests. Thanks for your suggestions.

[jiimaho]

Hi @reisenberger and thanks for your quick reply. I actually just found what I was looking for in Polly itself!

SystemClock.Sleep allows me to mock the internal timer for Polly, which causes the sleeps to really not sleep.

I closed the my issue as it’s not relevant anymore.

[reisenberger]

Thanks for that @rog1039 . The ability to manipulate Polly’s abstracted, ambient-context SystemClock is intended to provide exactly this: you can manipulate time so that tests which would otherwise incur a time delay, don’t. See the many tests within the existing codebase which do this.

Let us know how you get on with that - or if you can envisage ways it could be improved (I can envisage some - as ever, with trade-offs)

EDIT: Improved the Unit-testing wiki to highlight this.