{
					ApplyTo: networking.EnvoyFilter_LISTENER,
					Patch:   nil,
				},
			},
		}, error: "Envoy filter: missing patch"},
		{name: "invalid patch operation", in: &networking.EnvoyFilter{
			ConfigPatches: []*networking.EnvoyFilter_EnvoyConfigObjectPatch{
				{
					ApplyTo: networking.EnvoyFilter_LISTENER,
					Patch:   &networking.EnvoyFilter_Patch{},
				},
			},

			Match: &networking.EnvoyFilter_EnvoyConfigObjectMatch{
				Context: networking.EnvoyFilter_GATEWAY,
			},
			Patch: &networking.EnvoyFilter_Patch{
				Operation: networking.EnvoyFilter_Patch_ADD,
				Value:     buildPatchStruct(`{"name":"new-gateway-listener"}`),
			},
		},

		{
			ApplyTo: networking.EnvoyFilter_LISTENER,
			Match: &networking.EnvoyFilter_EnvoyConfigObjectMatch{

	if value == nil {
		// for remove ops
		return nil, nil
	}
	var obj proto.Message
	switch applyTo {
	case networking.EnvoyFilter_CLUSTER:
		obj = &cluster.Cluster{}
	case networking.EnvoyFilter_LISTENER:
		obj = &listener.Listener{}
	case networking.EnvoyFilter_ROUTE_CONFIGURATION:
		obj = &route.RouteConfiguration{}
	case networking.EnvoyFilter_FILTER_CHAIN:
		obj = &listener.FilterChain{}

				continue
			}
		}
		// ensure that applyTo, match and patch all line up
		switch cp.ApplyTo {
		case networking.EnvoyFilter_LISTENER,
			networking.EnvoyFilter_FILTER_CHAIN,
			networking.EnvoyFilter_NETWORK_FILTER,
			networking.EnvoyFilter_HTTP_FILTER:
			if cp.Match != nil && cp.Match.ObjectTypes != nil {

			// removed by another op
			continue
		}
		patchListener(patchContext, efw.Patches, lis, &listenersRemoved)
	}
	// adds at listener level if enabled
	if !skipAdds {
		for _, lp := range efw.Patches[networking.EnvoyFilter_LISTENER] {
			if lp.Operation == networking.EnvoyFilter_Patch_ADD {
				// If listener ADD patch does not specify a patch context, only add for sidecar outbound and gateway.

			},
		},
	}
	priorities := []int32{
		2, 1,
	}

	configPatches := []*networking.EnvoyFilter_EnvoyConfigObjectPatch{
		{
			ApplyTo: networking.EnvoyFilter_LISTENER,
			Match: &networking.EnvoyFilter_EnvoyConfigObjectMatch{
				Context: networking.EnvoyFilter_SIDECAR_OUTBOUND,
				Proxy: &networking.EnvoyFilter_ProxyMatch{
					Metadata: map[string]string{"foo": "sidecar"},

			}
			if len(filter.Patches[networking.EnvoyFilter_LISTENER]) != tt.expectedListenerPatches {
				t.Errorf("Expect %d envoy filter listener patches, but got %d", tt.expectedListenerPatches, len(filter.Patches[networking.EnvoyFilter_LISTENER]))
			}
		})
	}
}

func TestEnvoyFilterOrder(t *testing.T) {
	env := &Environment{}