Here is a list of websites for testing ad blockers and anti-viruses. Most of these webpages are setup to detect if you are using a browser based ad blocker, but you can still generate queries and see that ads are blocked.
Test ad blockers:
- https://blockads.fivefilters.org/
- https://thepcspy.com/blockadblock/
- http://www.angelfire.com/alt2/entertainment/ad_block_test.html
- https://canyoublockit.com/