public Collection<ComputeNodeInstance> loadAllComputeNodeInstances() {
        Collection<ComputeNodeInstance> result = new LinkedList<>();
        for (InstanceType each : InstanceType.values()) {
            result.addAll(loadComputeNodeInstances(each));
        }
        return result;
    }
@Test
    void assertLoadAllComputeNodeInstances() {
        when(repository.getChildrenKeys("/nodes/compute_nodes/online/jdbc")).thenReturn(Collections.singletonList("foo_instance_3307"));
        when(repository.getChildrenKeys("/nodes/compute_nodes/online/proxy")).thenReturn(Collections.singletonList("foo_instance_3308"));
        YamlComputeNodeData yamlComputeNodeData0 = new YamlComputeNodeData();
        yamlComputeNodeData0.setAttribute("127.0.0.1");
        yamlComputeNodeData0.setVersion("foo_version");
        when(repository.query("/nodes/compute_nodes/online/jdbc/foo_instance_3307")).thenReturn(YamlEngine.marshal(yamlComputeNodeData0));
        YamlComputeNodeData yamlComputeNodeData1 = new YamlComputeNodeData();
        yamlComputeNodeData1.setAttribute("127.0.0.1@3308");
        yamlComputeNodeData1.setVersion("foo_version");
        when(repository.query("/nodes/compute_nodes/online/proxy/foo_instance_3308")).thenReturn(YamlEngine.marshal(yamlComputeNodeData1));
        List<ComputeNodeInstance> actual = new ArrayList<>(new ComputeNodePersistService(repository).loadAllComputeNodeInstances());
        assertThat(actual.size(), is(2));
        assertThat(actual.get(0).getMetaData().getId(), is("foo_instance_3307"));
        assertThat(actual.get(0).getMetaData().getIp(), is("127.0.0.1"));
        assertThat(actual.get(1).getMetaData().getId(), is("foo_instance_3308"));
        assertThat(actual.get(1).getMetaData().getIp(), is("127.0.0.1"));
        assertThat(actual.get(1).getMetaData().getType(), is(InstanceType.PROXY));
        assertThat(((ProxyInstanceMetaData) actual.get(1).getMetaData()).getPort(), is(3308));
    }