benchmarks: Propagate errors in LoadWorkerTest startup

Also clean up resources at the end of test.

benchmarks/src/test/java/io/grpc/benchmarks/driver/LoadWorkerTest.java

@@ -19,6 +19,7 @@ package io.grpc.benchmarks.driver;
 import static com.google.common.truth.Truth.assertThat;
 import static org.junit.Assert.fail;
 
+import com.google.common.util.concurrent.SettableFuture;
 import io.grpc.ManagedChannel;
 import io.grpc.benchmarks.Utils;
 import io.grpc.benchmarks.proto.Control;
@@ -26,10 +27,9 @@ import io.grpc.benchmarks.proto.Stats;
 import io.grpc.benchmarks.proto.WorkerServiceGrpc;
 import io.grpc.netty.NettyChannelBuilder;
 import io.grpc.stub.StreamObserver;
-import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.TimeUnit;
-import java.util.concurrent.atomic.AtomicInteger;
+import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -51,6 +51,7 @@ public class LoadWorkerTest {
   private ManagedChannel channel;
   private WorkerServiceGrpc.WorkerServiceStub workerServiceStub;
   private LinkedBlockingQueue<Stats.ClientStats> marksQueue;
+  private StreamObserver<Control.ServerArgs> serverLifetime;
 
   @Before
   public void setup() throws Exception {
@@ -62,6 +63,18 @@ public class LoadWorkerTest {
     marksQueue = new LinkedBlockingQueue<>();
   }
 
+  @After
+  public void tearDown() {
+    if (serverLifetime != null) {
+      serverLifetime.onCompleted();
+    }
+    try {
+      WorkerServiceGrpc.newBlockingStub(channel).quitWorker(Control.Void.getDefaultInstance());
+    } finally {
+      channel.shutdownNow();
+    }
+  }
+
   @Test
   public void runUnaryBlockingClosedLoop() throws Exception {
     Control.ServerArgs.Builder serverArgsBuilder = Control.ServerArgs.newBuilder();
@@ -203,13 +216,13 @@ public class LoadWorkerTest {
   }
 
   private StreamObserver<Control.ClientArgs> startClient(Control.ClientArgs clientArgs)
-      throws InterruptedException {
-    final CountDownLatch clientReady = new CountDownLatch(1);
+      throws Exception {
+    final SettableFuture<Void> clientReady = SettableFuture.create();
     StreamObserver<Control.ClientArgs> clientObserver = workerServiceStub.runClient(
         new StreamObserver<Control.ClientStatus>() {
           @Override
           public void onNext(Control.ClientStatus value) {
-            clientReady.countDown();
+            clientReady.set(null);
             if (value.hasStats()) {
               marksQueue.add(value.getStats());
             }
@@ -217,45 +230,43 @@ public class LoadWorkerTest {
 
           @Override
           public void onError(Throwable t) {
+            clientReady.setException(t);
           }
 
           @Override
           public void onCompleted() {
+            clientReady.setException(
+                new RuntimeException("onCompleted() before receiving response"));
           }
         });
 
     // Start the client
     clientObserver.onNext(clientArgs);
-    if (!clientReady.await(TIMEOUT, TimeUnit.SECONDS)) {
-      fail("Client failed to start");
-    }
+    clientReady.get(TIMEOUT, TimeUnit.SECONDS);
     return clientObserver;
   }
 
-  private int startServer(Control.ServerArgs serverArgs) throws InterruptedException {
-    final AtomicInteger serverPort = new AtomicInteger();
-    final CountDownLatch serverReady = new CountDownLatch(1);
-    StreamObserver<Control.ServerArgs> serverObserver =
+  private int startServer(Control.ServerArgs serverArgs) throws Exception {
+    final SettableFuture<Integer> port = SettableFuture.create();
+    serverLifetime =
         workerServiceStub.runServer(new StreamObserver<Control.ServerStatus>() {
           @Override
           public void onNext(Control.ServerStatus value) {
-            serverPort.set(value.getPort());
-            serverReady.countDown();
+            port.set(value.getPort());
           }
 
           @Override
           public void onError(Throwable t) {
+            port.setException(t);
           }
 
           @Override
           public void onCompleted() {
+            port.setException(new RuntimeException("onCompleted() before receiving response"));
           }
         });
     // trigger server startup
-    serverObserver.onNext(serverArgs);
-    if (!serverReady.await(TIMEOUT, TimeUnit.SECONDS)) {
-      fail("Server failed to start");
-    }
-    return serverPort.get();
+    serverLifetime.onNext(serverArgs);
+    return port.get(TIMEOUT, TimeUnit.SECONDS);
   }
 }