private void verifyCohort(ProcedureMember member, int cohortSize, String operationName,
    byte[] data) {
    // verify(member, Mockito.times(cohortSize)).submitSubprocedure(Mockito.eq(operationName),
    // (byte[]) Mockito.argThat(new ArrayEquals(data)));
    Mockito.verify(member, Mockito.atLeast(cohortSize)).submitSubprocedure(Mockito.any());

  }
Verify the cohort controller got called once per expected node to start the operation
hbase-server/src/test/java/org/apache/hadoop/hbase/procedure/TestZKProcedureControllers.java