It is hard to debug some test failures because there isn't enough information logged to see where a failure happened.

The ReplSetTest JavaScript module calls its own getMaster() routine from many places, and users of ReplSetTest also call it. Because it is not based on any of the assert() functions, it prints no stack trace when it throws an exception, so there is no way to tell what function was calling it when it failed.

getMaster() should print a stack trace on failure to help debugging.