Aggregation failures #1
Description
If you perform an invalid aggregation, you get a RuntimeError because the counting stage of the aggregation pipeline will fail. This also happens if you're not connected to a proper mongod.
We probably can't do anything about this for now, but if anyone ever gets to integrate with the Python standard logging module we might be able to emit a better message.
This might happen with the query as well, but I'm not sure.