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[Python-Dev] flaky tests caused by repr() sort order

Tim Peters tim.peters at gmail.com
Thu Nov 21 18:57:11 CET 2013 
[Christian Heimes]
> the buildbots are flaky because two repr() tests for userdict and
> functools.partial fail every now and then. The test cases depend on a
> fixed order of keyword arguments the representation of userdict and
> partial instances. The improved hash randomization of PEP 456 shows its
> power. I haven't seen the issue before because it happens rarely and
> mostly on 32 bit platforms.
>
> http://bugs.python.org/issue19681
> http://bugs.python.org/issue19664
>
> I'm not sure about the best approach for the issues. Either we need to
> change the test case and make it more resilient or the code for repr()
> must sort its dict keys.

Best to change the failing tests.  For example, _they_ can sort the
dict keys if they rely on a fixed order.  Sorting in general is a
dubious idea because it can be a major expense with no real benefit
for most uses.
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