public Set<Integer> nodesThatShouldBeDown(ClusterState state) {
        return calculate(state).nodesThatShouldBeDown();
    }
@Test
    void min_ratio_per_group_is_closed_interval() {
        GroupAvailabilityCalculator calc = calcForHierarchicCluster(
                DistributionBuilder.withGroups(3).eachWithNodeCount(2), 0.50);
        assertThat(calc.nodesThatShouldBeDown(clusterState(
                "distributor:6 storage:6 .4.s:d")), equalTo(emptySet()));
    }