examples: migrate unittest examples to GrpcServerRule

migrated simple tests using `GrpcServerRule`.
Kept the low level in-process channel setup and tear down code for the RouteGuide example to show how users can use in-process directly to set more custom channel builder options when needed.

resolves #2490

examples/README.md

@@ -68,3 +68,7 @@ with a mock/fake service implementation.
 
 For testing a gRPC server, create the server as an InProcessServer,
 and test it against a real client stub with an InProcessChannel.
+
+The gRPC-java library also provides a JUnit rule,
+[GrpcServerRule](../testing/src/main/java/io/grpc/testing/GrpcServerRule.java), to do the starting
+up and shutting down boilerplate for you.

examples/build.gradle

@@ -29,6 +29,7 @@ dependencies {
   compile "io.grpc:grpc-protobuf:${grpcVersion}"
   compile "io.grpc:grpc-stub:${grpcVersion}"
 
+  testCompile "io.grpc:grpc-testing:${grpcVersion}"
   testCompile "junit:junit:4.11"
   testCompile "org.mockito:mockito-core:1.9.5"
 }

examples/pom.xml

@@ -28,6 +28,12 @@
       <artifactId>grpc-stub</artifactId>
       <version>${grpc.version}</version>
     </dependency>
+    <dependency>
+      <groupId>io.grpc</groupId>
+      <artifactId>grpc-testing</artifactId>
+      <version>${grpc.version}</version>
+      <scope>test</scope>
+    </dependency>
     <dependency>
       <groupId>junit</groupId>
       <artifactId>junit</artifactId>

examples/src/main/java/io/grpc/examples/helloworld/HelloWorldClient.java

@@ -37,12 +37,13 @@ public class HelloWorldClient {
     this(ManagedChannelBuilder.forAddress(host, port)
         // Channels are secure by default (via SSL/TLS). For the example we disable TLS to avoid
         // needing certificates.
-        .usePlaintext(true));
+        .usePlaintext(true)
+        .build());
   }
 
   /** Construct client for accessing RouteGuide server using the existing channel. */
-  HelloWorldClient(ManagedChannelBuilder<?> channelBuilder) {
+  HelloWorldClient(ManagedChannel channel) {
-    channel = channelBuilder.build();
+    this.channel = channel;
     blockingStub = GreeterGrpc.newBlockingStub(channel);
   }
 

examples/src/test/java/io/grpc/examples/header/HeaderClientInterceptorTest.java

@@ -21,9 +21,8 @@ import static org.junit.Assert.fail;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
 
-import io.grpc.ManagedChannel;
+import io.grpc.ClientInterceptors;
 import io.grpc.Metadata;
-import io.grpc.Server;
 import io.grpc.ServerCall;
 import io.grpc.ServerCall.Listener;
 import io.grpc.ServerCallHandler;
@@ -35,10 +34,8 @@ import io.grpc.examples.helloworld.GreeterGrpc.GreeterBlockingStub;
 import io.grpc.examples.helloworld.GreeterGrpc.GreeterImplBase;
 import io.grpc.examples.helloworld.HelloReply;
 import io.grpc.examples.helloworld.HelloRequest;
-import io.grpc.inprocess.InProcessChannelBuilder;
+import io.grpc.testing.GrpcServerRule;
-import io.grpc.inprocess.InProcessServerBuilder;
+import org.junit.Rule;
-import org.junit.After;
-import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
@@ -55,6 +52,12 @@ import org.mockito.Matchers;
  */
 @RunWith(JUnit4.class)
 public class HeaderClientInterceptorTest {
+  /**
+   * This creates and starts an in-process server, and creates a client with an in-process channel.
+   * When the test is done, it also shuts down the in-process client and server.
+   */
+  @Rule
+  public final GrpcServerRule grpcServerRule = new GrpcServerRule().directExecutor();
 
   private final ServerInterceptor mockServerInterceptor = spy(
       new ServerInterceptor() {
@@ -65,32 +68,12 @@ public class HeaderClientInterceptorTest {
         }
       });
 
-  private Server fakeServer;
-  private ManagedChannel inProcessChannel;
-
-  @Before
-  public void setUp() throws Exception {
-    String uniqueServerName = "fake server for " + getClass();
-    fakeServer = InProcessServerBuilder.forName(uniqueServerName)
-        .addService(ServerInterceptors.intercept(new GreeterImplBase() {}, mockServerInterceptor))
-        .directExecutor()
-        .build()
-        .start();
-    inProcessChannel = InProcessChannelBuilder.forName(uniqueServerName)
-        .intercept(new HeaderClientInterceptor())
-        .directExecutor()
-        .build();
-  }
-
-  @After
-  public void tearDown() {
-    inProcessChannel.shutdownNow();
-    fakeServer.shutdownNow();
-  }
-
   @Test
   public void clientHeaderDeliveredToServer() {
-    GreeterBlockingStub blockingStub = GreeterGrpc.newBlockingStub(inProcessChannel);
+    grpcServerRule.getServiceRegistry()
+        .addService(ServerInterceptors.intercept(new GreeterImplBase() {}, mockServerInterceptor));
+    GreeterBlockingStub blockingStub = GreeterGrpc.newBlockingStub(
+        ClientInterceptors.intercept(grpcServerRule.getChannel(), new HeaderClientInterceptor()));
     ArgumentCaptor<Metadata> metadataCaptor = ArgumentCaptor.forClass(Metadata.class);
 
     try {

examples/src/test/java/io/grpc/examples/header/HeaderServerInterceptorTest.java

@@ -26,21 +26,18 @@ import io.grpc.Channel;
 import io.grpc.ClientCall;
 import io.grpc.ClientInterceptor;
 import io.grpc.ForwardingClientCall.SimpleForwardingClientCall;
-import io.grpc.ManagedChannel;
 import io.grpc.Metadata;
 import io.grpc.MethodDescriptor;
-import io.grpc.Server;
 import io.grpc.ServerInterceptors;
 import io.grpc.examples.helloworld.GreeterGrpc;
 import io.grpc.examples.helloworld.GreeterGrpc.GreeterBlockingStub;
 import io.grpc.examples.helloworld.GreeterGrpc.GreeterImplBase;
 import io.grpc.examples.helloworld.HelloReply;
 import io.grpc.examples.helloworld.HelloRequest;
-import io.grpc.inprocess.InProcessChannelBuilder;
-import io.grpc.inprocess.InProcessServerBuilder;
 import io.grpc.stub.StreamObserver;
-import org.junit.After;
+import io.grpc.testing.GrpcServerRule;
 import org.junit.Before;
+import org.junit.Rule;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
@@ -56,12 +53,15 @@ import org.mockito.ArgumentCaptor;
  */
 @RunWith(JUnit4.class)
 public class HeaderServerInterceptorTest {
-  private Server fakeServer;
+  /**
-  private ManagedChannel inProcessChannel;
+   * This creates and starts an in-process server, and creates a client with an in-process channel.
+   * When the test is done, it also shuts down the in-process client and server.
+   */
+  @Rule
+  public final GrpcServerRule grpcServerRule = new GrpcServerRule().directExecutor();
 
   @Before
   public void setUp() throws Exception {
-    String uniqueServerName = "fake server for " + getClass();
     GreeterImplBase greeterImplBase =
         new GreeterImplBase() {
           @Override
@@ -70,18 +70,8 @@ public class HeaderServerInterceptorTest {
             responseObserver.onCompleted();
           }
         };
-    fakeServer = InProcessServerBuilder.forName(uniqueServerName)
+    grpcServerRule.getServiceRegistry()
-        .addService(ServerInterceptors.intercept(greeterImplBase, new HeaderServerInterceptor()))
+        .addService(ServerInterceptors.intercept(greeterImplBase, new HeaderServerInterceptor()));
-        .directExecutor()
-        .build()
-        .start();
-    inProcessChannel = InProcessChannelBuilder.forName(uniqueServerName).directExecutor().build();
-  }
-
-  @After
-  public void tearDown() {
-    inProcessChannel.shutdownNow();
-    fakeServer.shutdownNow();
   }
 
   @Test
@@ -103,8 +93,8 @@ public class HeaderServerInterceptorTest {
     }
 
     SpyingClientInterceptor clientInterceptor = new SpyingClientInterceptor();
-    GreeterBlockingStub blockingStub =
+    GreeterBlockingStub blockingStub = GreeterGrpc.newBlockingStub(grpcServerRule.getChannel())
-        GreeterGrpc.newBlockingStub(inProcessChannel).withInterceptors(clientInterceptor);
+        .withInterceptors(clientInterceptor);
     ArgumentCaptor<Metadata> metadataCaptor = ArgumentCaptor.forClass(Metadata.class);
 
     blockingStub.sayHello(HelloRequest.getDefaultInstance());

examples/src/test/java/io/grpc/examples/helloworld/HelloWorldClientTest.java

@@ -20,12 +20,10 @@ import static org.junit.Assert.assertEquals;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
 
-import io.grpc.Server;
-import io.grpc.inprocess.InProcessChannelBuilder;
-import io.grpc.inprocess.InProcessServerBuilder;
 import io.grpc.stub.StreamObserver;
-import org.junit.After;
+import io.grpc.testing.GrpcServerRule;
 import org.junit.Before;
+import org.junit.Rule;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
@@ -42,31 +40,22 @@ import org.mockito.Matchers;
  */
 @RunWith(JUnit4.class)
 public class HelloWorldClientTest {
-  private final GreeterGrpc.GreeterImplBase serviceImpl = spy(new GreeterGrpc.GreeterImplBase() {});
+  /**
+   * This creates and starts an in-process server, and creates a client with an in-process channel.
+   * When the test is done, it also shuts down the in-process client and server.
+   */
+  @Rule
+  public final GrpcServerRule grpcServerRule = new GrpcServerRule().directExecutor();
 
-  private Server fakeServer;
+  private final GreeterGrpc.GreeterImplBase serviceImpl = spy(new GreeterGrpc.GreeterImplBase() {});
   private HelloWorldClient client;
 
-  /**
-   * Creates and starts a fake in-process server, and creates a client with an in-process channel.
-   */
   @Before
   public void setUp() throws Exception {
-    String uniqueServerName = "fake server for " + getClass();
+    // Add service.
-    fakeServer = InProcessServerBuilder
+    grpcServerRule.getServiceRegistry().addService(serviceImpl);
-        .forName(uniqueServerName).directExecutor().addService(serviceImpl).build().start();
+    // Create a HelloWorldClient using the in-process channel;
-    InProcessChannelBuilder channelBuilder =
+    client = new HelloWorldClient(grpcServerRule.getChannel());
-        InProcessChannelBuilder.forName(uniqueServerName).directExecutor();
-    client = new HelloWorldClient(channelBuilder);
-  }
-
-  /**
-   * Shuts down the client and server.
-   */
-  @After
-  public void tearDown() throws Exception {
-    client.shutdown();
-    fakeServer.shutdownNow();
   }
 
   /**

examples/src/test/java/io/grpc/examples/helloworld/HelloWorldServerTest.java

@@ -18,13 +18,9 @@ package io.grpc.examples.helloworld;
 
 import static org.junit.Assert.assertEquals;
 
-import io.grpc.ManagedChannel;
-import io.grpc.Server;
 import io.grpc.examples.helloworld.HelloWorldServer.GreeterImpl;
-import io.grpc.inprocess.InProcessChannelBuilder;
+import io.grpc.testing.GrpcServerRule;
-import io.grpc.inprocess.InProcessServerBuilder;
+import org.junit.Rule;
-import org.junit.After;
-import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
@@ -39,30 +35,12 @@ import org.junit.runners.JUnit4;
  */
 @RunWith(JUnit4.class)
 public class HelloWorldServerTest {
-  private static final String UNIQUE_SERVER_NAME =
-      "in-process server for " + HelloWorldServerTest.class;
-  private final Server inProcessServer = InProcessServerBuilder
-      .forName(UNIQUE_SERVER_NAME).addService(new GreeterImpl()).directExecutor().build();
-  private final ManagedChannel inProcessChannel =
-      InProcessChannelBuilder.forName(UNIQUE_SERVER_NAME).directExecutor().build();
-
   /**
-   * Creates and starts the server with the {@link InProcessServerBuilder},
+   * This creates and starts an in-process server, and creates a client with an in-process channel.
-   * and creates an in-process channel with the {@link InProcessChannelBuilder}.
+   * When the test is done, it also shuts down the in-process client and server.
    */
-  @Before
+  @Rule
-  public void setUp() throws Exception {
+  public final GrpcServerRule grpcServerRule = new GrpcServerRule().directExecutor();
-    inProcessServer.start();
-  }
-
-  /**
-   * Shuts down the in-process channel and server.
-   */
-  @After
-  public void tearDown() {
-    inProcessChannel.shutdownNow();
-    inProcessServer.shutdownNow();
-  }
 
   /**
    * To test the server, make calls with a real stub using the in-process channel, and verify
@@ -70,7 +48,11 @@ public class HelloWorldServerTest {
    */
   @Test
   public void greeterImpl_replyMessage() throws Exception {
-    GreeterGrpc.GreeterBlockingStub blockingStub = GreeterGrpc.newBlockingStub(inProcessChannel);
+    // Add the service to the in-process server.
+    grpcServerRule.getServiceRegistry().addService(new GreeterImpl());
+
+    GreeterGrpc.GreeterBlockingStub blockingStub =
+        GreeterGrpc.newBlockingStub(grpcServerRule.getChannel());
     String testName = "test name";
 
     HelloReply reply = blockingStub.sayHello(HelloRequest.newBuilder().setName(testName).build());