test(gateway-api): add tests for custom backend filters

Signed-off-by: kahirokunn <okinakahiro@gmail.com>

pkg/router/gateway_api_test.go

@@ -276,6 +276,56 @@ func TestGatewayAPIRouter_Routes(t *testing.T) {
 		assert.Len(t, hr.Spec.Rules, 1)
 		assert.Len(t, hr.Spec.Rules[0].Filters, 0)
 	})
+
+	t.Run("custom backend filters", func(t *testing.T) {
+		canary := mocks.canary.DeepCopy()
+		primaryHostName := v1.PreciseHostname("primary.example.com")
+		canary.Spec.Service.Primary = &flaggerv1.CustomBackend{
+			Backend: &flaggerv1.HTTPBackendRefTemplate{
+				Filters: []v1.HTTPRouteFilter{
+					{
+						Type: v1.HTTPRouteFilterURLRewrite,
+						URLRewrite: &v1.HTTPURLRewriteFilter{
+							Hostname: &primaryHostName,
+						},
+					},
+				},
+			},
+		}
+
+		kind := v1.Kind("Service")
+		name := v1.ObjectName("canary")
+		namespace := v1.Namespace("kube-system")
+		port := v1.PortNumber(30080)
+		objRef := v1.BackendObjectReference{
+			Kind:      &kind,
+			Name:      name,
+			Namespace: &namespace,
+			Port:      &port,
+		}
+
+		canary.Spec.Service.Canary = &flaggerv1.CustomBackend{
+			Backend: &flaggerv1.HTTPBackendRefTemplate{
+				BackendObjectReference: &objRef,
+			},
+		}
+		err = router.SetRoutes(canary, 50, 50, false)
+		require.NoError(t, err)
+
+		httpRoute, err := router.gatewayAPIClient.GatewayapiV1().HTTPRoutes("default").Get(context.TODO(), "podinfo", metav1.GetOptions{})
+		require.NoError(t, err)
+
+		primary := httpRoute.Spec.Rules[0].BackendRefs[0]
+		assert.Equal(t, int32(50), *primary.Weight)
+
+		canaryBackend := httpRoute.Spec.Rules[0].BackendRefs[1]
+		assert.Equal(t, canaryBackend.Name, name)
+		assert.Equal(t, canaryBackend.Namespace, &namespace)
+		assert.Equal(t, canaryBackend.Port, &port)
+
+		primaryBackend := httpRoute.Spec.Rules[0].BackendRefs[0].Filters[0].URLRewrite
+		assert.Equal(t, primaryBackend.Hostname, &primaryHostName)
+	})
 }
 
 func TestGatewayAPIRouter_getSessionAffinityRouteRules(t *testing.T) {