TST: added tests for sparse and date range quantiles
- [x] closes #24600
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

Added tests for sparse and date range quantiles
I'm new to Travis CI and based on the error I am seeing in the error log I am not understanding what is causing the issue: `requests.exceptions.ChunkedEncodingError: ("Connection broken: ConnectionResetError(104, 'Connection reset by peer')", ConnectionResetError(104, 'Connection reset by peer'))`.

Anyone have any insight into what would cause this? thanks @sanders41 