TST: Local conftest for test_offsets.py

[GuessWhoSamFoo]

• closes xxxxx
• tests added / passed
• passes git diff upstream/master -u -- "*.py" | flake8 --diff

Continued from #17622 per comments. Looks like offset_types property can be replaced entirely with a fixture.

[codecov]

Codecov Report

Merging #17825 into master will decrease coverage by 0.04%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master   #17825      +/-   ##
==========================================
- Coverage   91.26%   91.22%   -0.05%     
==========================================
  Files         163      163              
  Lines       49980    49980              
==========================================
- Hits        45613    45592      -21     
- Misses       4367     4388      +21

Flag	Coverage Δ
#multiple	89.02% <100%> (-0.03%)	⬇️
#single	40.24% <100%> (-0.07%)	⬇️

Impacted Files	Coverage Δ
pandas/tests/tseries/conftest.py	96.77% <100%> (ø)
pandas/io/gbq.py	25% <0%> (-58.34%)	⬇️
pandas/plotting/_converter.py	63.38% <0%> (-1.82%)	⬇️
pandas/core/frame.py	97.74% <0%> (-0.1%)	⬇️
pandas/tests/indexes/conftest.py

---

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[codecov]

Codecov Report

Merging #17825 into master will decrease coverage by 0.04%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master   #17825      +/-   ##
==========================================
- Coverage   91.26%   91.22%   -0.05%     
==========================================
  Files         163      163              
  Lines       49980    49980              
==========================================
- Hits        45613    45592      -21     
- Misses       4367     4388      +21

Flag	Coverage Δ
#multiple	89.02% <100%> (-0.03%)	⬇️
#single	40.24% <100%> (-0.07%)	⬇️

Impacted Files	Coverage Δ
pandas/tests/tseries/conftest.py	96.77% <100%> (ø)
pandas/io/gbq.py	25% <0%> (-58.34%)	⬇️
pandas/plotting/_converter.py	63.38% <0%> (-1.82%)	⬇️
pandas/core/frame.py	97.74% <0%> (-0.1%)	⬇️
pandas/tests/indexes/conftest.py

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 9f0ee53...69db510. Read the comment docs.

[jreback]

thanks!

keem em coming!