TST: Add tests for fixed issues
- [x] closes #13230
- [x] closes #13820
- [x] closes #13758
- [x] closes #13228
- [x] closes #13208
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`

lgtm. if you'd update to @simonjayhawkins comments, then merge on green.