TST: dont break ABCPandasArray checks

[jbrockmendel]

Apparently tests.extension.tests_numpy patches PandasArray._typ so as to break all isinstance(obj, ABCPandasArray) checks. Learning this in the process of troubleshooting failing tests is really frustrating. This is a code smell and should be removed.

[TomAugspurger]

Can you clarify? The patch is leaking between tests?

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On Sun, Jun 23, 2019 at 9:59 PM jbrockmendel ***@***.***> wrote: Apparently tests.extension.tests_numpy patches PandasArray._typ so as to break all isinstance(obj, ABCPandasArray) checks. Learning this in the process of troubleshooting failing tests is really frustrating. This is a code smell and should be removed. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#27014?email_source=notifications&email_token=AAKAOIUIRVZ7EKIPUUBZLBLP4A2CRA5CNFSM4H22RXC2YY3PNVWWK3TUL52HS4DFUVEXG43VMWVGG33NNVSW45C7NFSM4G3F5WMQ>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAKAOIUYP2OPEH6KVCEYC4DP4A2CRANCNFSM4H22RXCQ> .

[jbrockmendel]

The patch caused a bunch of failures while putting together #27015 (eventually I had to just disable the entire test file). What is the compelling reason to change the behavior for these tests?

[jorisvandenbossche]

What is the compelling reason to change the behavior for these tests?

Because we currently don't allow actually storing them, I think (and that hack is then a way to test them being stored)

[jbrockmendel]

Because we currently don't allow actually storing them, I think (and that hack is then a way to test them being stored)

So we want to test that if we allow something that we dont allow, then that thing is allowed?

[TomAugspurger]

We want to test that PandasArray correctly implements the EA interface, part of which requires allowing it to be stored in a Series / DataFrame.