@Test
    void distribution_config_change_triggers_new_versioned_state_bundle_with_updated_config() throws Exception {
        var f = new DistributionConfigInBundleFixture(true);
        int oldVersion = ctrl.getClusterStateBundle().getVersion();

        var newDistrCfg = DistributionBuilder.configForFlatCluster(8);
        f.updateWithNewConfig(newDistrCfg);

        int newVersion = ctrl.getClusterStateBundle().getVersion();
        assertThat(newVersion, greaterThan(oldVersion));
        var bundleCfg = ctrl.getClusterStateBundle().distributionConfig();
        assertTrue(bundleCfg.isPresent());
        assertEquals(newDistrCfg, bundleCfg.get().config());
    }
Class for testing states of all nodes. Will fail in constructor with
debug message on non-expected results.
clustercontroller-core/src/test/java/com/yahoo/vespa/clustercontroller/core/StateChangeTest.java