config: Update remote URL handling.

luci_config/server/cfgclient/backend/testconfig/local_service.go

Index: luci_config/server/cfgclient/backend/testconfig/local_service.go
diff --git a/luci_config/server/cfgclient/backend/testconfig/local_service.go b/luci_config/server/cfgclient/backend/testconfig/local_service.go
index 97e04b008e6b6a4fdeeee783eb784cf119910ed7..9e3dc01b2296c7394348a9ae15162aebe2b893f8 100644
--- a/luci_config/server/cfgclient/backend/testconfig/local_service.go
+++ b/luci_config/server/cfgclient/backend/testconfig/local_service.go
@@ -41,6 +41,14 @@ type Provider struct {
 
 var _ client.Provider = (*Provider)(nil)
 
+// GetServiceURL implements ClientProvider.
+func (p *Provider) GetServiceURL() url.URL {
+	return url.URL{
+		Scheme: "test",
+		Host:   "example.com",
+	}
+}
+
 // GetConfigClient implements ClientProvider.
 func (p *Provider) GetConfigClient(c context.Context, a backend.Authority) ccfg.Interface {
 	return &boundLocalInterface{