cmd/protoc-gen-go-grpc: add change detector test

.github/workflows/testing.yml

@@ -123,3 +123,6 @@ jobs:
           interop/interop_test.sh
           echo -e "\n-- Running xDS E2E Test --"
           xds/internal/test/e2e/run.sh
+          echo -e "\n-- Running protoc-gen-go-grpc test --"
+          ./scripts/vet-proto.sh -install
+          cmd/protoc-gen-go-grpc/protoc-gen-go-grpc_test.sh

cmd/protoc-gen-go-grpc/README.md

@@ -13,7 +13,7 @@ change from the grpc code generator previously included with `protoc-gen-go`.
 To restore this behavior, set the option `require_unimplemented_servers=false`.
 E.g.:
 
-```
+```sh
   protoc --go-grpc_out=. --go-grpc_opt=require_unimplemented_servers=false[,other options...] \
 ```
 

cmd/protoc-gen-go-grpc/proto/golden.proto

@@ -0,0 +1,34 @@
+// Copyright 2024 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.
+
+syntax = "proto3";
+
+option go_package = "testdata/proto";
+
+package main;
+
+message EventRequest {
+  bytes content = 1;
+}
+
+message EventResponse {
+  bytes content = 1;
+}
+
+service BidirectionalStreamingService {
+  rpc unaryMethod(EventRequest) returns (EventResponse) {}
+  rpc clientMethod(stream EventRequest) returns (EventResponse) {}
+  rpc serverMethod(EventRequest) returns (stream EventResponse) {};
+  rpc bidirectionalMethod(stream EventRequest) returns (stream EventResponse) {}
+}

cmd/protoc-gen-go-grpc/protoc-gen-go-grpc_test.sh

@@ -0,0 +1,47 @@
+#!/bin/bash
+# Copyright 2024 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.
+
+# Uncomment to enable debugging.
+# set -x 
+
+WORKDIR="$(dirname $0)"
+TEMPDIR=$(mktemp -d)
+
+trap "rm -rf ${TEMPDIR}" EXIT
+
+# Build protoc-gen-go-grpc binary and add to $PATH.
+pushd "${WORKDIR}"
+go build -o "${TEMPDIR}" . 
+PATH="${TEMPDIR}:${PATH}"
+popd
+
+protoc \
+    --go-grpc_out="${TEMPDIR}" \
+    --go-grpc_opt=paths=source_relative \
+    "$WORKDIR/proto/golden.proto"
+
+GOLDENFILE="${WORKDIR}/testdata/golden_grpc.pb.go"
+GENFILE=$(find "${TEMPDIR}" -name "golden_grpc.pb.go")
+
+DIFF=$(diff "${GOLDENFILE}" "${GENFILE}")
+if [[ -n "${DIFF}" ]]; then
+    echo -e "ERROR: Generated file golden_grpc.pb.go differs from golden file:\n${DIFF}"
+    echo -e "If you have made recent changes to protoc-gen-go-grpc," \
+     "please regenerate the golden files by running:" \
+     "\n\t go generate google.golang.org/grpc/..." >&2
+    exit 1
+fi
+
+echo SUCCESS