The expect_query helper function seems to be flakey when using sharded cluster topology. I'm not sure exactly why but my guess is that the driver is making multiple "child" queries to each shard, causing the expected query count to be off.

The following specs are affected for example:

• Mongoid::Association::Referenced::BelongsTo::Eager.includes when the association is polymorphic when eager loading multiple associations loads all associations eagerly
• Mongoid::Contextual::Mongo#estimated_count when the query cache is enabled the results are not cached
• Mongoid::Criteria::Includable When multiple associations reference the same class executes a query for the non-retrieved elements
• Mongoid::Criteria::Includable When multiple parent_inclusions for the same association when including an association and using each twice on a criteria eager loads the criteria