Running nose with IronPython

I just spent the past week at the 2009 Microsoft MVP Summit where I got a chance to talk to the some of the crew behind the dynamic languages at Microsoft. When I mentioned that I had gotten nose, a Python unit testing framework, working with IronPython, I was strongly encouraged to blog about it. Without further adieu, here's my code.

import sys
sys.path.append(r"C:\Python25\Lib\site-packages\nose-0.10.4-py2.5.egg")
sys.path.append(r"C:\python25\lib")
sys.path.append(r"C:\Python25\Lib\email")
sys.path.append(r"C:\Python25\Scripts")
import nose
nose.main()

I dropped this script into a directory with a couple of bogus unit tests and ran it with Python 2.5.4. Results were consistent with my expectations - successful tests passed and failing tests threw exceptions. When I ran the same suite against IronPython 2.0.0, I still received the correct results but the script took 1 minute and 20 seconds to complete. Compare that to less than a second (estimated) for CPython. For the sake of completeness, I ran the same test with IronPython 2.0.1 and received the same result.

The root of the problem appears to be the large number of GeneratorExitExceptions being thrown. I'm not sure why they're being thrown, but I'll continue to investigate and report my findings. If you're interested in the gory details, here's the stack trace of the first exception:

at IronPython.Runtime.PythonGenerator.ThrowThrowable()
at IronPython.Runtime.PythonGenerator.CheckThrowable()
at IronPython.Runtime.PythonGenerator.
CheckThrowableAndReturnSendValue()
at IronPython.Runtime.Operations.PythonOps.
GeneratorCheckThrowableAndReturnSendValue(Object self)
at S$11.lambda_method$312(Closure , Int32& state, Object& current) in C:\python25\lib\types.py:line 52
at Microsoft.Scripting.Runtime.GeneratorEnumerator`1.
System.Collections.IEnumerator.MoveNext()
at IronPython.Runtime.PythonGenerator.MoveNextWorker()
at IronPython.Runtime.PythonGenerator.System.
Collections.IEnumerator.MoveNext()
at IronPython.Runtime.PythonGenerator.throw(Object type, Object value, Object traceback)
at IronPython.Runtime.PythonGenerator.throw(Object type)
at IronPython.Runtime.PythonGenerator.close()