auto clusters = GetClusters(*graph);
  EXPECT_EQ(4, clusters.size());
  EXPECT_EQ(clusters["B"], clusters["C"]);
  EXPECT_EQ(clusters["E"], clusters["F"]);
  EXPECT_NE(clusters["B"], clusters["E"]);
  EXPECT_TRUE(clusters.find("A") == clusters.cend());
  EXPECT_TRUE(clusters.find("D") == clusters.cend());
}

TEST(XlaCompilationTest, UncompilableCycles) {

_Extracts head or tail outside compilation to separate host launches before/after device cluster._

This pass extracts a CPU computation cluster with `_xla_outside_compilation`
annotation from the head or tail of a Device cluster.

For example:

```mlir
  %cluster = "tf_device.cluster"() ( {
    %a = "tf.A"(%arg0) {_xla_outside_compilation = "cluster1"} : (tensor<i32>) -> tensor<i32>
    %b = "tf.B"(%a) : (tensor<i32>) -> tensor<i32>

	cases := []struct {
		name    string
		cluster cluster.ID
		network network.ID
	}{
		{
			name:    "values unset",
			cluster: "",
			network: "",
		},
		{
			name:    "values set",
			cluster: testC,
			network: testNW,
		},
	}

	for _, c := range cases {
		t.Run(c.name, func(t *testing.T) {
			s := newAmbientTestServer(t, c.cluster, c.network)

            echo "This script starts a local kube cluster. "
            echo "Example 0: hack/local-up-cluster.sh -h  (this 'help' usage description)"
            echo "Example 1: hack/local-up-cluster.sh -o _output/dockerized/bin/linux/amd64/ (run from docker output)"
            echo "Example 2: hack/local-up-cluster.sh -O (auto-guess the bin path for your platform)"
            echo "Example 3: hack/local-up-cluster.sh (build a local copy of the source)"

// CHECK-NEXT: _replication_info = "replicate"
// CHECK-SAME: device = "/device:TPU:0"
// CHECK-SAME: topology = "topology"
// CHECK:      return %[[CLUSTER]]#0, %[[CLUSTER]]#1, %[[CLUSTER]]#2


// Test a nested user of an op in a cluster has its operand be updated to
// `tf_device.cluster` result.
// CHECK-LABEL: func @nested_cluster_op_user
// CHECK-SAME: (%[[ARG_0:[a-z0-9]*]]: tensor<i1>)

  // Returns true if the devices in `cluster_a` and `cluster_b` are compatible
  // and therefore not a hindrance for combining the two clusters into a larger
  // cluster.
  absl::StatusOr<bool> AreDevicesCompatible(const Cluster& cluster_a,
                                            const Cluster& cluster_b);

  void DumpPostClusteringGraphs();
  void VLogClusteringSummary();

      "5m",
      "15m",
      "1h",
      "6h",
      "12h",
      "24h",
      "2d",
      "7d",
      "30d"
    ]
  },
  "timezone": "",
  "title": "MinIO Cluster Replication Dashboard",
  "uid": "TgmJnnqnk3",
  "version": 1,
  "weekStart": ""

				Dest:      "alt-known.default.svc.cluster.local",
			}},
			proxy:     proxy("not-default"),
			routeName: "8080",
			expected: map[string][]string{
				"known.default.svc.cluster.local": {"outbound|8080||alt-known.default.svc.cluster.local"},
			},
			expectedGateway: map[string][]string{
				"known.default.svc.cluster.local": {"outbound|8080||known.default.svc.cluster.local"},
			},

			service: &model.Service{
				Hostname:       "echo.default.svc.cluster.local",
				MeshExternal:   false,
				DefaultAddress: "1.2.3.4",
				ClusterVIPs: model.AddressMap{
					Addresses: map[cluster.ID][]string{
						"cluster-1": {"1.2.3.4", "2406:3003:2064:35b8:864:a648:4b96:e37d"},
						"cluster-2": {"4.3.2.1"}, // ensure other clusters aren't being populated in domains slice
					},
				},
			},
			port: 8123,

			// Ideally, if the weighted cluster overwrites authority, it has precedence. This mirrors behavior of headers,
			// because for headers we append the weighted last which allows it to Set and wipe out previous Adds.
			// However, Envoy behavior is different when we set at both cluster level and route level, and we want
			// behavior to be consistent with a single cluster and multiple clusters.