unittest: assertRaises() with an instance instead of a type
ulrich.eckhardt at dominolaser.com
Thu Mar 29 09:28:15 CEST 2012
Am 28.03.2012 20:26, schrieb Terry Reedy:
> On 3/28/2012 8:28 AM, Ulrich Eckhardt wrote:
>> with self.assertRaises(MyException(SOME_FOO_ERROR)):
> I presume that if this worked the way you want, all attributes would
> have to match. The message part of builtin exceptions is allowed to
> change, so hard-coding an exact expected message makes tests fragile.
> This is a problem with doctest.
I would have assumed that comparing two exceptions leaves out messages
that are intended for the user, not as part of the API. However, my
expectations aren't met anyway, because ...
>> This of course requires the exception to be equality-comparable.
> Equality comparison is by id. So this code will not do what you want.
>>> Exception('foo') == Exception('foo')
Yikes! That was unexpected and completely changes my idea. Any clue
whether this is intentional? Is identity the fallback when no equality
is defined for two objects?
Thanks for your feedback!
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