l := s.Listeners(proxy)
	sim := &Simulation{
		t:         t,
		Listeners: l,
		Clusters:  s.Clusters(proxy),
		Routes:    s.RoutesFromListeners(proxy, l),
	}
	return sim
}

func NewSimulation(t *testing.T, s *xds.FakeDiscoveryServer, proxy *model.Proxy) *Simulation {
	return NewSimulationFromConfigGen(t, s.ConfigGenTest, proxy)
}

// withT swaps out the testing struct. This allows executing sub tests.

	runTest := func(t *testing.T) {
		o.ConfigString = tt.config
		o.KubernetesObjectString = tt.kubeConfig
		s := xds.NewFakeDiscoveryServer(t, o)
		sim := simulation.NewSimulation(t, s, s.SetupProxy(proxy))
		sim.RunExpectations(tt.calls)
		if t.Failed() && debugMode {
			t.Log(xdstest.MapKeys(xdstest.ExtractClusters(sim.Clusters)))
			t.Log(xdstest.ExtractListenerNames(sim.Listeners))

					if err != nil {
						t.Fatal(err)
					}
					s := xds.NewFakeDiscoveryServer(t, xds.FakeOptions{
						Configs:           istio,
						KubernetesObjects: kubeo,
					})
					sim := simulation.NewSimulation(t, s, s.SetupProxy(tt.proxy))
					xdstest.ValidateListeners(t, sim.Listeners)
					xdstest.ValidateRouteConfigurations(t, sim.Routes)
					r := xdstest.ExtractRouteConfigurations(sim.Routes)
					vh := r[tt.routeName]