Mocking Timers to speed up tests?

Hi
If you are using the Timer class than you will run into the mscorlib problem.
TypeMock can not mock the mscorlib types. :evil:
The workaround is to create a wrapper class around the Timer class and than mock your class.
Hope it helps.

Hi,
Nice question. There are several issues here.
First: What Timer are you using?
There are 3 timers in .NET

:arrow: System.Threading.Timer
As this is defined in mscorlib, there is no way to mock it.
As Ohad wrote there is a simple way to overcome this buy wrapping the Timer in you own class.

:arrow: System.Timers.Timer
There are a two ways:
1. Change the intreval to 1ms using the swap parameters:

Mock mock = MockManager.Mock(typeof (Timer), Constructor.NotMocked);
mock.ExpectSetAlways("Interval").Args(new Assign((double)1));

2. Mock the event and fire it.

Mock mock = MockManager.Mock(typeof (Timer), Constructor.NotMocked);
MockedEvent handler = mock.ExpectAddEvent("Elapsed");
//
   ...
// fire the event
handler.Fire(null, null);

:arrow: System.Windows.Forms.Timer
Same as System.Timers.Timer but the event is "Tick"
1. Change Interval

Mock mock = MockManager.Mock(typeof (Timer), Constructor.NotMocked);
mock.ExpectSetAlways("Interval").Args(new Assign((double)1));

2. Fire the Event

Mock mock = MockManager.Mock(typeof (Timer), Constructor.NotMocked);
MockedEvent handler = mock.ExpectAddEvent("Tick");
//
   ...
// fire the event
handler.Fire(null, null);

Thanks gents,
I ran into the mscorlib mocking problem and yes, I did decide to wrap the construction of the System.Threading.Timer.

So what I have done within the test, is mock the helper, and return a timer that does nothing. So within the class under test, no state transitions are made by the timer any more. I then allowed my test to _manually_ trigger a state transition through an internal method.

This approach is really so much better than I had hoped - it allows for much finer control of the object under test during different scenarios.

For safety, I have a single test which validates that when the timer is not mocked, that the state transitions are made within the time limts etc.

Cheers!
Pete
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