Open Stack

Whoops, that should say "assertions" not "exceptions".

----- Original Message -----
> From: "Solly Ross" <sross at redhat.com>
> To: "OpenStack Development Mailing List (not for usage questions)" <openstack-dev at lists.openstack.org>
> Sent: Monday, November 24, 2014 12:00:44 AM
> Subject: Re: [openstack-dev] [nova] Proposal new hacking rules
> 
> Well, at least the message for exceptions in Nova says "expected" and
> "observed".
> I suspect that it's part of our custom test case classes.
> 
> Best Regards,
> Solly Ross
> 
> 
> ----- Original Message -----
> > From: "Matthew Treinish" <mtreinish at kortar.org>
> > To: "OpenStack Development Mailing List (not for usage questions)"
> > <openstack-dev at lists.openstack.org>
> > Sent: Friday, November 21, 2014 5:23:28 PM
> > Subject: Re: [openstack-dev] [nova] Proposal new hacking rules
> > 
> > On Fri, Nov 21, 2014 at 04:15:07PM -0500, Sean Dague wrote:
> > > On 11/21/2014 01:52 PM, Matthew Treinish wrote:
> > > > On Fri, Nov 21, 2014 at 07:15:49PM +0100, jordan pittier wrote:
> > > >> Hey,
> > > >> I am not a Nova developer but I still have an opinion.
> > > >>
> > > >>> Using boolean assertions
> > > >> I like what you propose. We should use and enforce the assert* that
> > > >> best
> > > >> matches the intention. It's about semantic and the more precise we
> > > >> are,
> > > >> the better.
> > > >>
> > > >>> Using same order of arguments in equality assertions
> > > >> Why not. But I don't know how we can write a Hacking rule for this. So
> > > >> you may fix all the occurrences for this now, but it might get back in
> > > >> the future.
> > > > 
> > > > Ok I'll bite, besides the enforceability issue which you pointed out,
> > > > it
> > > > just
> > > > doesn't make any sense, you're asserting 2 things are equal: (A == B)
> > > > ==
> > > > (B == A)
> > > > and I honestly feel that it goes beyond nitpicking because of that.
> > > > 
> > > > It's also a fallacy that there will always be an observed value and an
> > > > expected value. For example:
> > > > 
> > > >   self.assertEqual(method_a(), method_b())
> > > > 
> > > > Which one is observed and which one is expected? I think this proposal
> > > > is
> > > > just
> > > > reading into the parameter names a bit too much.
> > > 
> > > If you are using assertEqual with 2 variable values... you are doing
> > > your test wrong.
> > > 
> > > I was originally in your camp. But honestly, the error message provided
> > > to the user does say expected and observed, and teaching everyone that
> > > you have to ignore the error message is a much harder thing to do than
> > > flip the code to conform to it, creating less confusion.
> > > 
> > 
> > Uhm, no it doesn't, the default error message is "A != B". [1][2][3] (both
> > with
> > unittest and testtools) If the error message was like that, then sure
> > saying
> > one way was right over the other would be fine, (assuming you didn't
> > specify
> > a
> > different error message) but, that's not what it does.
> > 
> > 
> > [1]
> > https://github.com/testing-cabal/testtools/blob/master/testtools/testcase.py#L340
> > [2]
> > https://github.com/testing-cabal/testtools/blob/master/testtools/matchers/_basic.py#L85
> > [3]
> > https://hg.python.org/cpython/file/301d62ef5c0b/Lib/unittest/case.py#l508
> > 
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> > 
>