See http://kilfour.wordpress.com/2009/12/27/mr-bad-example/.

[SpecFor(typeof(BugRun))]
public Spec ShrinksIrrelevantInput(int input, bool output)
{
return new Spec(() => Ensure.True(output));
}
}


it doesn’t really create random tests… it uses randomly generated data (which as Mark said, you have full control over if you need/want it) to execute the transitions and verify the specs that you’ve defined. There’s more to it because the previous sentence is quite an over-simplification but i just want to avoid any confusion with regards to creating random tests.

It’s still a pretty young framework, in beta, and the upcoming next release allready contains a ‘small’ breaking change (SetUp became Setup). I’m trying to keep these things to an absolute minimum though.
Documentation is not yet available, buth forthcoming in the very near future. Follow the links on google code for the blog and discussion group.

1. Yes, full control if you want, default generators are available if you don’t need full control.
2. The framework reports the simplest failcase :

An acid test for this buggy class :

public class BugHouse
{
private int count;
public bool Run(int a)
{
if (count++ >= 3 && a == 6)
throw new Exception();
return true;
}
}

returns the following console output :

—— Test started: Assembly: QuickNet.Example.dll ——

TestCase ‘BugRun ShrinksIrrelevantInput’ failed: System.Exception : Exception of type ‘System.Exception’ was thrown.
D:\DotNetDev\QN\QuickNet.Example\SimpleTransitionShrinking.cs(16,0): at QuickNet.Example.BugHouse.Run(Int32 a)
D:\DotNetDev\QN\QuickNet.Example\SimpleTransitionShrinking.cs(58,0): at QuickNet.Example.UsingGenerator.BugRun.b__3(Int32 input)
D:\DotNetDev\QN\QuickNet\Transition.cs(55,0): at QuickNet.Transition`2.PerformTransition(TestRunReport report)

Output from BugRun ShrinksIrrelevantInput:
———————————————————-
BugRun ShrinksIrrelevantInput
Falsifiable after 1 test(s), 40 Transition(s).
——————–Simplest Fail Case——————–
Transition : BugRun, Output : True
Transition : BugRun, Output : True
Transition : BugRun, Output : True
Transition : BugRun, Output : True
6
———————————————————-

0 passed, 1 failed, 0 skipped, took 1,13 seconds.

This means that calling BugHouse.Run 3 times with any input and then once again with 6 as a parameter causes an exception.

‘Is it reproducable ?’
Once it hits a fail case, it will hit it again. You might have to tweak some values to get to the edge-cases more often. Currently it is not very debugger-friendly. You pretty much want to debug the simplest fail case and not the entire run, this is currently not possible. I’m working on improving that.