auth: Make luci-go services trust signatures produced by the token server.

server/auth/auth_test.go

Index: server/auth/auth_test.go
diff --git a/server/auth/auth_test.go b/server/auth/auth_test.go
index 025de5b10852c131c9d4299557ef74e2f55844dd..da25ea9b57b3c289dd5fd4f7001c59fd3478bf55 100644
--- a/server/auth/auth_test.go
+++ b/server/auth/auth_test.go
@@ -17,6 +17,7 @@ import (
 	"github.com/luci/luci-go/server/auth/authdb"
 	"github.com/luci/luci-go/server/auth/identity"
 	"github.com/luci/luci-go/server/auth/service/protocol"
+	"github.com/luci/luci-go/server/auth/signing"
 
 	. "github.com/luci/luci-go/common/testing/assertions"
 	. "github.com/smartystreets/goconvey/convey"
@@ -155,6 +156,10 @@ func (db *fakeDB) SharedSecrets(c context.Context) (secrets.Store, error) {
 	return nil, errors.New("fakeDB: SharedSecrets is not implemented")
 }
 
+func (db *fakeDB) GetCertificates(c context.Context, id identity.Identity) (*signing.PublicCertificates, error) {
+	return nil, errors.New("fakeDB: GetCertificates is not implemented")
+}
+
 func (db *fakeDB) GetWhitelistForIdentity(c context.Context, ident identity.Identity) (string, error) {
 	return "", nil
 }