twisted.trial.runner.filenameToModule should not swallow unrelated exceptions

New submission from arkanes <[email protected]>:

When converting a filename to a module for running with trial, filenameToModule first tries reflect.namedAny, checks for ValueError or AttributeError, and then falls back to imp.load_source. This implicitly assumes that when an exception is raised when importing a module, importing it again (via imp) will either fail the same way or succeed normally (if the file was fixed in a race condition or something). In the specific case of extension modules, this is not true - they leave module objects in sys.modules if they raise an exception when imported.

This is a Python bug but the way trial does this import exacerbates the issue.

Helpfully, reflect.namedAny raises more specific exceptions that filenameToModule should catch instead.

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Type     : defect
Component: runner
Keywords : 
Priority : normal
Nosy     : 
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http://twistedmatrix.com/trac/ticket/4134