TST: timeseries tests reorg

[jreback]

Datetime

• We have some DatetimeIndex tests in here and some in here and a lot here (PR #14854: DatetimeIndex compiled together in test_datetime.py #15266)

we can separate these out to a single file in pandas/tests/indexes/test_datetime.py
The Base class (which powers lots of tests for the sub-classes DatetimeIndex, PeriodIndex, TimedeltaIndex), can move to pandas/tests/indexes/tests_datetimelike.py (and merge with the existing Datetimelike class).

• create a pandas/tests/scalar/test_timestamp.py with Timestamp specific tests
  There are a lot of tests also in tseries/test_tslib.py, that can be merged into test_timestamp.py

• the residuals (from tests_timeseries.py are Series tests speficially, these can move to pandas/tests/series/test_timeseries.py

Legacy Tests

• timeseries_legacy need a look, but can prob be deleted

Period

• same idea with Period, the actual Period tests can be moved to tests/scalar/test_period.py, but move the index tests to tests/indexes/test_period.py (which can be stripped from here and here)

Timedelta

• same idea with Timedelta, the actual Timedelta tests can be moved to tests/scalar/test_timedelta.py but move the index tests to tests/indexes/test_timedelta.py (which can be stripped from here and here)

[TrigonaMinima]

@jreback Is anyone working on this?

[jreback]

nope - go for it

do this is discrete mergeable pieces

[TrigonaMinima]

@jreback I have started with pandas/tests/indexes/test_datetime.py first. I am not that familiar with the codebase. I might ask a few questions here and there, if that's okay with you. Like, this TestDateTimeIndexToJulianDate class looks like it should be sent to test_datetime.py. Is it okay to copy-paste the whole class and test it there?

[jreback]

yes

[TrigonaMinima]

Will these tests come under test_datetimeindex_accessors()?

[jreback]

@TrigonaMinima not sure what you mean.

Let me espouse the general idea here. Keep individual tests exactly the same (and classes as much as possible). We want to first simply move things around to group similar things together.

Next phases can dive deeper.