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

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.
e.g.:
 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.
-Andrew.