Method TestGoodUpdateThenResolverError

balancer/lazy/lazy_ext_test.go:193–295

Tests the scenario when a resolver produces a good state followed by a resolver error. The test verifies that the child balancer receives the good update followed by the error.

(t *testing.T)

// resolver error. The test verifies that the child balancer receives the good
// update followed by the error.
func (s) TestGoodUpdateThenResolverError(t *testing.T) {
	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
	defer cancel()

	backend := stubserver.StartTestService(t, nil)
	defer backend.Stop()
	resolverStateReceived := false
	resolverErrorReceived := grpcsync.NewEvent()

	childBF := stub.BalancerFuncs{
		Init: func(bd *stub.BalancerData) {
			bd.ChildBalancer = balancer.Get(pickfirst.Name).Build(bd.ClientConn, bd.BuildOptions)
		},
		UpdateClientConnState: func(bd *stub.BalancerData, ccs balancer.ClientConnState) error {
			if resolverErrorReceived.HasFired() {
				t.Error("Received resolver error before resolver state.")
			}
			resolverStateReceived = true
			return bd.ChildBalancer.UpdateClientConnState(ccs)
		},
		ResolverError: func(bd *stub.BalancerData, err error) {
			if !resolverStateReceived {
				t.Error("Received resolver error before resolver state.")
			}
			resolverErrorReceived.Fire()
			bd.ChildBalancer.ResolverError(err)
		},
		Close: func(bd *stub.BalancerData) {
			bd.ChildBalancer.Close()
		},
	}

	childBalName := strings.ReplaceAll(strings.ToLower(t.Name())+"_child", "/", "")
	stub.Register(childBalName, childBF)

	topLevelBF := stub.BalancerFuncs{
		Init: func(bd *stub.BalancerData) {
			bd.ChildBalancer = lazy.NewBalancer(bd.ClientConn, bd.BuildOptions, balancer.Get(childBalName).Build)
		},
		ExitIdle: func(*stub.BalancerData) {
			t.Log("Ignoring call to ExitIdle to delay lazy child creation until RPC time.")
		},
		ResolverError: func(bd *stub.BalancerData, err error) {
			bd.ChildBalancer.ResolverError(err)
		},
		UpdateClientConnState: func(bd *stub.BalancerData, ccs balancer.ClientConnState) error {
			return bd.ChildBalancer.UpdateClientConnState(ccs)
		},
		Close: func(bd *stub.BalancerData) {
			bd.ChildBalancer.Close()
		},
	}

	topLevelBalName := strings.ReplaceAll(strings.ToLower(t.Name())+"_top_level", "/", "")
	stub.Register(topLevelBalName, topLevelBF)

	json := fmt.Sprintf(`{"loadBalancingConfig": [{%q: {}}]}`, topLevelBalName)