TST: test_assert_index check index attributes

[sinhrks]

• PeriodIndex.freq (mandatory), TST/ERR: Add Period ops tests / fix error message #13250
• DatetimeIndex.tz (mandatory)
• DatetimeIndex.freq (add check_freq option with default False, because lots of tests compare op result (lost freq) and expected result created by date_range (has freq))
• TimedeltaIndex.freq (same as above), TST/ERR: Add Period ops tests / fix error message #13250
• CategoricalIndex internals (.codes and .categories) (ref TST: assert_series/frame not comparing for categoricals #13076, add check_categorical with default True), PR #TST: check internal Categorical #13249

[sinhrks]

I already have a branch which checks PeriodIndex.freq currently fails in empty resampling (being fixed by #13079).

https://github.com/sinhrks/pandas/tree/test_periodindex

[max-sixty]

How about comparing the attr dictionaries (._get_attribute_dict()), rather than having the separate lookup above?
That could also include name

[sinhrks]

There are mandatory and optional check. For example, our tests do something like assert_frame_equal(df.a, df.b, check_names=False). Also, we have pickle tests to skip some attribute check like Categorical.ordered

[jreback]

@sinhrks I checked the freq boxes which I think closed by #13250

[sinhrks]

Thanks. Because #13250 only covers PeriodIndex, modified the boxes.

[jreback]

ok great!