[Python-Dev] How far to go with user-friendliness

Erik Bray erik.m.bray at gmail.com
Mon Jul 20 20:30:17 CEST 2015

On Tue, Jul 14, 2015 at 6:22 PM, Robert Collins
<robertc at robertcollins.net> wrote:
> For clarity, I think we should:
>  - remove the assret check, it is I think spurious.
>  - add a set of functions to the mock module that should be used in
> preference to Mock.assert*
>  - mark the Mock.assert* functions as PendingDeprecation
>  - in 3.6 move the PendingDeprecation to Deprecated
>  - in 3.7 remove the Mock.assert* functions and the check for method
> names beginning with assert entirely.

Hi all,

I'm just an onlooker, and haven't read every word of this thread.  In
fact I worry that it's pointless to reply to rather than starting a
new thread.  I just wanted to make sure that the specific message I'm
replying too wasn't lost in the noise because I think Robert's
suggestion makes vastly more sense than anything else I've seen here
(I came searching through the thread to see if anyone else suggested
this before I started a thread to do so).

I don't think it makes any sense to have magic assert_ methods on the
Mock object.  Not only does the "magic" clearly lead to too many
ambiguities and other problems--I think they make less sense from an
API standpoint in the first place.  Typically asserting something in a
test is not something an object *does*--a method.  More often we as a
test writers assert something *about* an object.  The assertion is an
external tool meant to measure and introspect things about the system
under observation.  In this case, although Mock is itself a testing
tool, we're introspecting something about the Mock object as external

***Assertions on Mock objects should be implemented as stand-alone
functions (that happen to be used primarily on Mock objects as

Aside from, in my mind, making more sense philosophically, using
specialized assert functions for this has absolutely none of the
spelling ambiguities or other problems of the magic methods.

I'm -0 on removing the assret_ methods unless no one is using them
yet.  I don't care if they're there as long as they're deprecated
along with the other magic methods of Mock.


More information about the Python-Dev mailing list