examples: add regression test script to hello world example (#3092)

.travis.yml

@@ -37,3 +37,4 @@ script:
   - if [[ "${GAE}" = 1 ]]; then make testappengine; exit 0; fi
   - if [[ "${RACE}" = 1 ]]; then make testrace; exit 0; fi
   - make test
+  - examples/helloworld/helloworld_test.sh

examples/helloworld/greeter_client/main.go

@@ -36,7 +36,7 @@ const (
 
 func main() {
 	// Set up a connection to the server.
-	conn, err := grpc.Dial(address, grpc.WithInsecure())
+	conn, err := grpc.Dial(address, grpc.WithInsecure(), grpc.WithBlock())
 	if err != nil {
 		log.Fatalf("did not connect: %v", err)
 	}

examples/helloworld/helloworld_test.sh

@@ -0,0 +1,93 @@
+#!/bin/bash
+ 
+#  Copyright 2019 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.
+# 
+
+set +e
+
+clean () {
+    jobs -p | xargs -n 1 pkill -P
+    wait
+}
+
+fail () {
+    echo "$(tput setaf 1) $1 $(tput sgr 0)"
+    clean
+    exit 1
+}
+
+pass () {
+    echo $"$(tput setaf 2) $1 $(tput sgr 0)"
+}
+
+# Build greeter server
+if ! go build -o /dev/null ./examples/helloworld/greeter_server/*.go; then
+    fail "failed to build greeter server"
+else
+    pass "successfully built greeter server"
+fi
+
+# Build greeter client
+if ! go build -o /dev/null ./examples/helloworld/greeter_client/*.go; then
+    fail "failed to build greeter client"
+else
+    pass "successfully built greeter client"
+fi
+
+# Server should be able to start
+SERVER_LOG="$(mktemp)"
+go run examples/helloworld/greeter_server/*.go &> $SERVER_LOG & 
+
+# Client should be able to communicate to the active server
+CLIENT_LOG="$(mktemp)"
+if ! go run examples/helloworld/greeter_client/*.go &> $CLIENT_LOG; then
+    fail "client failed to communicate with server
+    Got server log:
+    $(cat $SERVER_LOG)
+    Got client log:
+    $(cat $CLIENT_LOG)
+    "
+else
+    pass "client successfully communicated with server"
+fi
+
+# Out log should contain the string 'Received: world'
+# from the server.
+if ! grep -q "Received: world" $SERVER_LOG; then
+    fail "Server log missing server output: 'Received: world'
+    Got server log:
+    $(cat $SERVER_LOG)
+    Got client log:
+    $(cat $CLIENT_LOG)
+    "
+else
+    pass "Server log contains server output: 'Received: world'"
+fi
+
+# Out log should contain the string 'Greeting: Hello world'
+# from the client.
+if ! grep -q "Greeting: Hello world" $CLIENT_LOG ; then
+    fail "Client log missing client output: 'Greeting: Hello world'
+    Got server log:
+    $(cat $SERVER_LOG)
+    Got client log:
+    $(cat $CLIENT_LOG)
+    "
+else
+    pass "Client log contains client output: 'Greeting: Hello world'"
+fi
+
+clean
+