add test to check type of df column after loc()
- [x] closes #23326
- [x] All [code checks passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit).

Hey @mroeschke, I'd like to start writing tests for a lot of the existing GH issues. I am learning as I go, so I am not sure if something like this is sufficient and/or in the right place. Any critical feedback would be greatly appreciated so I can start writing better and more complex tests. Thanks! Awesome! Definitely check out https://pandas.pydata.org/docs/dev/development/contributing_codebase.html#using-pytest for all the details of how tests ideally should be structured and what should be included Hello @jackgoldsmith4! Thanks for updating this PR. We checked the lines you've touched for [PEP 8](https://www.python.org/dev/peps/pep-0008) issues, and found:



There are currently no PEP 8 issues detected in this Pull Request. Cheers! :beers: 

##### Comment last updated at 2022-06-12 18:18:15 UTC Thanks @jackgoldsmith4 