Looks very interesting.  What would be cool would be building a Message Sequence Chart [1] using Mondrian for model interactions.
For example, given a model root, Spy on all subclass methods, then from workspace invoke a starting method from which to trace. 
Or, more advanced, be able to invoke this from the debugger.

cheers -ben

[1] http://en.wikipedia.org/wiki/Message_Sequence_Chart

Alexandre Bergel wrote: 
Hi!

  
I'm was exploring some methods to build method wrappers and I discovered Spy.
Unfortunately the sample code provided on http://www.moosetechnology.org/tools/Spy does not run.
    

I have updated the webpage. It was a bit desynchronized with the actual code.
You may want to have a look at http://bergel.eu/download/papers/Berg10f-Spy.pdf
This is a longer description of the framework

  
When you reach this point

    
You can simply invoke it with:

| packageSpy |
packageSpy := DemoTestCoveragePackageSpy runTestAndGatherForPackageNamed: 'Mondrian'.
      
There is no "DemoTestCoveragePackageSpy" yet. 
    

You need to define 4 classes, as indicated in the webpage.

  
Afterward this class is defined but still there is no message "runTestAndGatherForPackageNamed".
    

use instead:
runTestsForPackagesMatching: 'YourPackages*'

Let us know if you still experience problems.

Cheers,
Alexandre