A part of the MONGODB-AWS work involved ensuring that monitoring connections did not authenticate, which had the unintended side effect of breaking Topology#connect for the unified topology. The reason is that the current implementation of connect is to execute a server selection for a given or default readPreference, but that no longer takes authentication into account. Switching the implementation to use ping works for integration tests, but requires an extra branch to be added to every use of the mock server. The easiest workaround for the moment was to change the implementation of Topology#connect to only run ping if some credentials were provided.