When running patch builds with new tests, I found what looks to be a failure in replica set auth tests (on master, with no code changes):

https://evergreen.mongodb.com/version/59e0c3e32fbabe44f60068e2

The failure is in the test Client/authenticate_cached/pool with the error:

tests/test-mongoc-client.c:474 test_mongoc_client_authenticate_cached(): testing The cachekey broke didn't log "Failed authentication"

We didn't run into this because no replica set tests with auth are being run, even though we have the tasks defined. Maybe I'm missing something, and those tests were removed intentionally? If so, then we should remove them from config.yml. Otherwise, that test failure may be legitimate.

FYI reproducing this locally may be a little annoying, since mlaunch has an open bug when creating replica-sets with auth