private void assertGroupSize(VespaModel model, String configId, int size) {
        StorDistributionConfig.Builder builder = new StorDistributionConfig.Builder();
        model.getConfig(builder, configId);
        StorDistributionConfig cfg = new StorDistributionConfig(builder);
        assertEquals(size, cfg.group().size());
    }
Test for creating cluster controllers under the admin tag.
config-model/src/test/java/com/yahoo/vespa/model/admin/ClusterControllerTestCase.java