[pytest-dev] Allow pytest.raises to assert about exception arguments

[holger krekel]

On Mon, Oct 14, 2013 at 17:19 +0200, Vladimir Keleshev wrote:
> Right now one of my code-bases is filled with assertions like:
> 
> with raises(SpecificError) as error:
>     some_action()
> assert 'specific message' == str(error)
> 
> Why not change `raises` to allow instances of exceptions as well:
> 
> with raises(SpecificError('specific message')):
>     some_action()

This depends on defining equality on the exception object, i guess.
For example:

>>> KeyError("hello") == KeyError("hello")
False

So it doesn't seem to be defined by default.  Of course we could do
something ourselves but i am not sure how reliable that would be.
Experiment if you like :)

holger


> I think, this can improve readability of `raises` assertions. Can't even think of immediate downsides of this.
> 
> What do you think?
> 
> —Vladimir
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