diff --git a/vendor/google.golang.org/grpc/Makefile b/vendor/google.golang.org/grpc/Makefile
index db982aa..410f7d5 100644
--- a/vendor/google.golang.org/grpc/Makefile
+++ b/vendor/google.golang.org/grpc/Makefile
@@ -19,6 +19,9 @@
 test: testdeps
 	go test -cpu 1,4 -timeout 7m google.golang.org/grpc/...
 
+testsubmodule: testdeps
+	cd security/advancedtls && go test -cpu 1,4 -timeout 7m google.golang.org/grpc/security/advancedtls/...
+
 testappengine: testappenginedeps
 	goapp test -cpu 1,4 -timeout 7m google.golang.org/grpc/...