IMO its better to comment all sample tests (to give an example how test could be implemented) and leave the decision to write them or not to the user as it done in most katas.

Sample tests for ruby is invalid. Test are failing because open(url) performs the actual network request, getting the most recent data and tests is based on old data. Also if you try to submit solution (by pressing attempt button) even if sample test failing, it will be accepted (if it working properly), this is very confusing.

I think the solution should be to stub network requests or use hidden tests (i'm not sure however is it possible to hide the body of process_data_sol and build_leaderboard from user until he solves this kata).