pubsub: remove obsolete doc references (#1823)

This PR removes references to the deprecated code of the docs.
The emulator section is rewritten.

Fixes #1789.

Author: pongad

README.md

@@ -586,29 +586,31 @@ Google Cloud Pub/Sub (Alpha)
 Here is a code snippet showing a simple usage example from within Compute Engine/App Engine
 Flexible. Note that you must [supply credentials](#authentication) and a project ID if running this
 snippet elsewhere. Complete source code can be found at
-[CreateSubscriptionAndPullMessages.java](./google-cloud-examples/src/main/java/com/google/cloud/examples/pubsub/snippets/CreateSubscriptionAndPullMessages.java).
+[CreateTopicAndPublishMessages.java](./google-cloud-examples/src/main/java/com/google/cloud/examples/pubsub/snippets/CreateTopicAndPublishMessages.java).
 
 ```java
-import com.google.cloud.pubsub.Message;
-import com.google.cloud.pubsub.PubSub;
-import com.google.cloud.pubsub.PubSub.MessageConsumer;
-import com.google.cloud.pubsub.PubSub.MessageProcessor;
-import com.google.cloud.pubsub.PubSubOptions;
-import com.google.cloud.pubsub.Subscription;
-import com.google.cloud.pubsub.SubscriptionInfo;
-
-try (PubSub pubsub = PubSubOptions.getDefaultInstance().getService()) {
-  Subscription subscription =
-      pubsub.create(SubscriptionInfo.of("test-topic", "test-subscription"));
-  MessageProcessor callback = new MessageProcessor() {
-    @Override
-    public void process(Message message) throws Exception {
-      System.out.printf("Received message \"%s\"%n", message.getPayloadAsString());
-    }
-  };
-  // Create a message consumer and pull messages (for 60 seconds)
-  try (MessageConsumer consumer = subscription.pullAsync(callback)) {
-    Thread.sleep(60_000);
+import com.google.api.gax.core.ApiFuture;
+import com.google.cloud.pubsub.spi.v1.Publisher;
+import com.google.cloud.pubsub.spi.v1.TopicAdminClient;
+import com.google.protobuf.ByteString;
+import com.google.pubsub.v1.PubsubMessage;
+import com.google.pubsub.v1.TopicName;
+
+TopicName topic = TopicName.create("test-project", "test-topic");
+try (TopicAdminClient topicAdminClient = TopicAdminClient.create()) {
+  topicAdminClient.createTopic(topic);
+}
+
+Publisher publisher = null;
+try {
+  publisher = Publisher.newBuilder(topic).build();
+  ByteString data = ByteString.copyFromUtf8("my message");
+  PubsubMessage pubsubMessage = PubsubMessage.newBuilder().setData(data).build();
+  ApiFuture<String> messageId = publisher.publish(pubsubMessage);
+  System.out.println("published with message ID: " + messageId.get());
+} finally {
+  if (publisher != null) {
+    publisher.shutdown();
   }
 }
 ```

TESTING.md

@@ -145,44 +145,36 @@ uses the `RemoteLoggingHelper` to create a metric.
 
 ### Testing code that uses Pub/Sub
 
-#### On your machine
-
-You can test against a temporary local Pub/Sub by following these steps:
-
-1. Start the local Pub/Sub emulator before running your tests using `LocalPubSubHelper`'s `create`
-and `start` methods. This will bind a port for communication with the local Pub/Sub emulator.
-  ```java
-  LocalPubSubHelper helper = LocalPubSubHelper.create();
-
-  helper.start(); // Starts the local Pub/Sub emulator in a separate process
-  ```
+You can test against a Pub/Sub emulator:
 
-2. Create and use a `PubSub` object with the options given by the `LocalPubSubHelper` instance. For
-example:
-  ```java
-  PubSub localPubsub = helper.getOptions().getService();
-  ```
-
-3. Run your tests.
+1. [Install Cloud SDK](https://cloud.google.com/sdk/downloads)
 
-4. Stop the local Pub/Sub emulator by calling the `stop()` method, like so:
-  ```java
-  helper.stop();
-  ```
-
-#### On a remote machine
+2. Start the emulator:
+```shell
+$ gcloud beta emulators pubsub start
+```
 
-You can test against a remote Pub/Sub emulator as well. To do this, set the `PubSubOptions` project
-endpoint to the hostname of the remote machine, like the example below.
+To determine which host/port the emulator is running on:
+```shell
+$ gcloud beta emulators pubsub env-init
+# Sample output:
+#   export PUBSUB_EMULATOR_HOST=localhost:8759
+```
 
-  ```java
-  PubSubOptions options = PubSubOptions.newBuilder()
-      .setProjectId("my-project-id") // must match project ID specified on remote machine
-      .setHost("<hostname of machine>:<port>")
-      .setCredentials(NoCredentials.getInstance())
-      .build();
-  PubSub localPubsub = options.getService();
-  ```
+3. Point your client to the emulator.
+```java
+ChannelProvider channelProvider =
+    // SubscriptionAdminSettings works too.
+    TopicAdminSettings.defaultChannelProviderBuilder()
+        .setEndpoint(System.getenv("PUBSUB_EMULATOR_HOST"))
+        .setCredentialsProvider(
+            FixedCredentialsProvider.create(NoCredentials.getInstance()))
+        .build();
+TopicAdminClient topicClient = TopicAdminClient.create(
+    TopicAdminSettings.defaultBuilder().setChannelProvider(channelProvider).build());
+Publisher publisher =
+    Publisher.newBuilder(topicName).setChannelProvider(channelProvider).build();
+```
 
 ### Testing code that uses Resource Manager