@Override
    public Set<ContainerModel> group(Set<TaskModel> taskModels, List<String> containersIds) {
      throw new UnsupportedOperationException("This should not be called");
    }
Groups all SSPs into two tasks. The first task gets all of the SSPs with a partition id of 0. The second task gets
all other SSPs. This is used for testing a custom {@link SystemStreamPartitionGrouper}.
samza-core/src/test/java/org/apache/samza/coordinator/TestJobModelCalculator.java