Run Isort on tests/series single pr
- [x] partial #23334
- [x] tests added / passed
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
Run `isort -rc pandas/tests/series/`
Hello @thoo! Thanks for updating the PR.

 - There are no PEP8 issues in the file [`pandas/tests/series/common.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/common.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/conftest.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/conftest.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/indexing/test_alter_index.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/indexing/test_alter_index.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/indexing/test_boolean.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/indexing/test_boolean.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/indexing/test_datetime.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/indexing/test_datetime.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/indexing/test_iloc.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/indexing/test_iloc.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/indexing/test_indexing.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/indexing/test_indexing.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/indexing/test_loc.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/indexing/test_loc.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/indexing/test_numeric.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/indexing/test_numeric.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/test_alter_axes.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/test_alter_axes.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/test_analytics.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/test_analytics.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/test_api.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/test_api.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/test_apply.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/test_apply.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/test_arithmetic.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/test_arithmetic.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/test_asof.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/test_asof.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/test_combine_concat.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/test_combine_concat.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/test_constructors.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/test_constructors.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/test_datetime_values.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/test_datetime_values.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/test_dtypes.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/test_dtypes.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/test_duplicates.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/test_duplicates.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/test_internals.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/test_internals.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/test_io.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/test_io.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/test_missing.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/test_missing.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/test_operators.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/test_operators.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/test_period.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/test_period.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/test_quantile.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/test_quantile.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/test_rank.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/test_rank.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/test_replace.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/test_replace.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/test_repr.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/test_repr.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/test_sorting.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/test_sorting.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/test_subclass.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/test_subclass.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/test_timeseries.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/test_timeseries.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/test_timezones.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/test_timezones.py) !

 - There are no PEP8 issues in the file [`pandas/tests/series/test_validate.py`](https://github.com/thoo/pandas/blob/43b2d225cd39de99344cd88afa10ab67e0bbe29c/pandas/tests/series/test_validate.py) !

 # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/23344?src=pr&el=h1) Report
> Merging [#23344](https://codecov.io/gh/pandas-dev/pandas/pull/23344?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/f662c5f2a7b392ee96a43f055073c8523f8f0339?src=pr&el=desc) will **not change** coverage.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/23344/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/23344?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #23344   +/-   ##
=======================================
  Coverage   92.22%   92.22%           
=======================================
  Files         169      169           
  Lines       51261    51261           
=======================================
  Hits        47277    47277           
  Misses       3984     3984
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.66% <ø> (ø)` | :arrow_up: |
| #single | `42.23% <ø> (ø)` | :arrow_up: |


------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/23344?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/23344?src=pr&el=footer). Last update [f662c5f...412a813](https://codecov.io/gh/pandas-dev/pandas/pull/23344?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 @jreback  For this one, I have to drop `test_duplicates.py`  because there might be a bug in `code_checks.sh`. It thought `test_duplicates.py` wasn't properly `isort`. Other than that, it is green. thanks @thoo 