@Override
      public Void answer(InvocationOnMock invocation) throws Throwable {
        controller.sendMemberCompleted(sub, memberData);
        committed.countDown();
        return null;
      }
Smaller test to just test the actuation on the cohort member
@throws Exception on failure
hbase-server/src/test/java/org/apache/hadoop/hbase/procedure/TestZKProcedureControllers.java