[Python-Dev] Unittest PEP do's and don'ts (BDFL pronouncement)

Andrew Bennetts andrew-pythondev at puzzling.org
Thu Jul 17 02:22:52 CEST 2008

Michael Foord wrote:
> Raymond Hettinger wrote:
>> If some people want to proceed down the path of "useful additions",
>> I challenge them to think bigger.  Give me some test methods that
>> improve my life.  Don't give me thirty ways to spell something I can
>> already do.
> I assert that... the following changes do meet those conditions:
> assertRaisesWithMessage - for testing the error messages from library  
> functions, where the error message is part of the API under test (I'm  
> less convinced with the need for a regex matching version myself.)

This one is easily solved by making assertRaises return the exception it caught.

    exc = self.assertRaises(AttributeError, getattr, foo, 'bar')
    self.assertEqual("'Foo' object has no attribute 'bar'", exc.message)

At least Twisted and bzr have already made this exact change.  It requires no new
methods, and is more flexible than the proposed assertRaisesWithMessage.


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