trial needs something to check DeprecationWarning

[therve]

There is a method in test_process.ProcessTestCase that asserts that a function call produce a warning. It's a bit like util.supress, but with checking the content of the warning, and I think that would be great for the deprecation policy.

[jml]

I've added something like this in the setUpClass-2303-2 branch (currently stalled due to lack of gtk1 support in feisty).

[exarkun]

Where in that branch is the relevant code? I looked around for a minute but I didn't see any likely candidates. I was going to split it out into a separate branch so we could go ahead with this without waiting for #2303.

[jml]

t.trial.util.collectWarnings. It isn't quite what's described, but it's the first step.

[therve]

Note that it's in the ireporter-2164 branch, no setUpClass-2303.

[therve]

Ready to review in assert-warn-2626.

[exarkun]

Looks nice. A few things:

• No coverage for the code which suppresses the __warningregistry__ for the function being tested (covering that probably just involves using assertWarn twice with the same function)
• I think args and kwargs should be *args and **kwargs. If this is a practical problem for someone, we can fix it later (by defining all the positional arguments with *args).
• assertWarns closes matches the naming style of assertRaises
• The function being tested might result in multiple warnings; there's no way to test such a function the way assertWarn works now. It'd be fine to defer that functionality to another ticket/time though.

[therve]

I've addressed the 3 points. The last functionality could be useful, but I don't think that's a high priority.

[ralphm]

Reviewed the last change set. Looking good. Please merge.

Maybe create a ticket for the latter point raised by exarkun?

[therve]

(In [20485]) Merge assert-warn-2626

Author: therve Reviewer: ralphm, exarkun Fixes #2626

Add an assertWarns method on unittest.TestCase that allows to check a warning is emitted when a function is called.