@Test(expected = NodeAllocationException.class)
    public void multiple_groups_are_on_separate_parent_hosts() {
        ProvisioningTester tester = new ProvisioningTester.Builder().zone(new Zone(Environment.prod, RegionName.from("us-east"))).flavorsConfig(flavorsConfig()).build();
        tester.makeReadyNodes(5, "host-small", NodeType.host, 32);
        tester.activateTenantHosts();

        //Deploy an application having 6 nodes (3 nodes in 2 groups). We only have 5 hosts available
        ApplicationId application1 = ProvisioningTester.applicationId();
        tester.prepare(application1, clusterSpec("myContent.t1.a1"), 6, 2, new NodeResources(1, 4, 100, 1));

        fail("Two groups have been allocated to the same parent host");
    }
Test redeployment of nodes that violates spare headroom - but without alternatives
<p>
Setup 2 hosts and allocate one app with a container on each. 2 spares
<p>
Initial allocation of app 1 --> final allocation:
<p>
|    |    |        |    |    |
|    |    |   -->  |    |    |
| 1a | 1b |        | 1a | 1b |
node-repository/src/test/java/com/yahoo/vespa/hosted/provision/provisioning/DynamicAllocationTest.java