service_entry_point_shard_role.cpp is at 70% code coverage right now, and service_entry_point_shard_role_helpers.h is at 61% code coverage. As these files have significant amounts of parsing code & logic, writing unit tests would be very useful for developer productivity. 

For example, unit tests would have sped up development on SERVER-85791 significantly as small changes were made to the class logic. Unit tests would also enable us to delete often flaky jstests that test metrics/parsing logic in the SEP.