TST: Test type issue fix in empty groupby from DataFrame with categorical
TST: Test type issue fix in empty groupby from DataFrame with categorical

closes #9614 
Hello @louishuynh! 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 2019-11-12 19:05:15 UTC thanks @louishuynh 