Add script to update gRPC submodule and run tests

test-grpc-submodule.sh

@@ -0,0 +1,28 @@
+#!/bin/sh
+# Copyright 2017 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# This script updates the gRPC submodule to a given reference and run tests
+
+cd packages/grpc-native-core/deps/grpc/
+
+# PR references are needed to test PRs from grpc/grpc
+git fetch --tags --progress https://github.com/grpc/grpc.git +refs/pull/*:refs/remotes/origin/pr/*
+git checkout $@
+git submodule update --init
+cd ../../../..
+
+packages/grpc-native-core/tools/buildgen/generate_projects.sh
+
+./run-tests.sh