Method TestWeightedTarget

balancer/weightedtarget/weightedtarget_test.go:212–394

TestWeightedTarget covers the cases that a sub-balancer is added and a sub-balancer is removed. It verifies that the addresses and balancer configs are forwarded to the right sub-balancer. This test is intended to test the glue code in weighted_target. It also tests an empty target config update, wh

(t *testing.T)

// glue code in weighted_target. It also tests an empty target config update,
// which should trigger a transient failure state update.
func (s) TestWeightedTarget(t *testing.T) {
	cc := testutils.NewBalancerClientConn(t)
	wtb := wtbBuilder.Build(cc, balancer.BuildOptions{})
	defer wtb.Close()

	// Start with "cluster_1: round_robin".
	config1, err := wtbParser.ParseConfig([]byte(`
{
  "targets": {
    "cluster_1": {
      "weight":1,
      "childPolicy": [{"round_robin": ""}]
    }
  }
}`))
	if err != nil {
		t.Fatalf("failed to parse balancer config: %v", err)
	}

	// Send the config, and an address with hierarchy path ["cluster_1"].
	addr1 := resolver.Address{Addr: testBackendAddrStrs[1], Attributes: nil}
	if err := wtb.UpdateClientConnState(balancer.ClientConnState{
		ResolverState: resolver.State{Endpoints: []resolver.Endpoint{
			hierarchy.SetInEndpoint(resolver.Endpoint{Addresses: []resolver.Address{addr1}}, []string{"cluster_1"}),
		}},
		BalancerConfig: config1,
	}); err != nil {
		t.Fatalf("failed to update ClientConn state: %v", err)
	}
	verifyAddressInNewSubConn(t, cc, addr1)

	// Send subconn state change.
	sc1 := <-cc.NewSubConnCh
	sc1.UpdateState(balancer.SubConnState{ConnectivityState: connectivity.Connecting})
	<-cc.NewPickerCh
	sc1.UpdateState(balancer.SubConnState{ConnectivityState: connectivity.Ready})
	p := <-cc.NewPickerCh

	// Test pick with one backend.
	for i := 0; i < 5; i++ {
		gotSCSt, _ := p.Pick(balancer.PickInfo{})
		if gotSCSt.SubConn != sc1 {
			t.Fatalf("picker.Pick, got %v, want SubConn=%v", gotSCSt, sc1)
		}
	}

	// Remove cluster_1, and add "cluster_2: test_config_balancer". The
	// test_config_balancer adds an address attribute whose value is set to the
	// config that is passed to it.
	config2, err := wtbParser.ParseConfig([]byte(`
{
  "targets": {
    "cluster_2": {
       "weight":1,
       "childPolicy": [{"test_config_balancer": "cluster_2"}]
    }
  }
}`))