Clean up LocalGcdHelper and docs (#821)

* Cleans up local gcd helper and docs to be more consistent with other test helpers
* Renames LocalGcdHelper to LocalDatastoreHelper and RemoteGcsHelper to RemoteStorageHelper
* Updates the gcd.sh script version

Author: ajkannan

TESTING.md

@@ -11,55 +11,64 @@ This library provides tools to help write tests for code that uses the following
 
 #### On your machine
 
-You can test against a temporary local datastore by following these steps:
+You can test against a temporary local Datastore by following these steps:
 
-1. Start the local datastore emulator using `LocalGcdHelper`.  This can be done in two ways:
-  - Run `LocalGcdHelper.java`'s `main` method with arguments `START` and (optionally) `--port=<port number>`.  This will create a temporary folder on your computer and bind `localhost:<port number>` for communication with the local datastore.  The port number is an optional argument.  If no port number is specified, port 8080 will be used.
-  - Call `LocalGcdHelper.start(<project ID>, <port number>)` before running your tests.  Save the `LocalGcdHelper` object returned so that you can stop the emulator later.
+1. Start the local Datastore emulator before running your tests using `LocalDatastoreHelper`'s `create` and `start` methods. This will create a temporary folder on your computer and bind a port for communication with the local Datastore. There is an optional argument for `create`: consistency. The consistency setting controls the fraction of Datastore writes that are immediately visible in global queries.
+  ```java
+  // Use the default consistency setting of 0.9
+  LocalDatastoreHelper helper = LocalDatastoreHelper.create();
+  // or explicitly set the consistency
+  helper = LocalDatastoreHelper.create(0.6);
+
+  helper.start(); // Starts the local Datastore emulator in a separate process
+  ```
 
-2. In your program, create and use a datastore whose host is set host to `localhost:<port number>`.  For example, 
+2. Create and use a `Datastore` object with the options given by the `LocalDatastoreHelper` instance.  For example:
   ```java
-  DatastoreOptions options = DatastoreOptions.builder()
-      .projectId(PROJECT_ID)
-      .host("http://localhost:8080")
-      .build();
-  Datastore localDatastore = options.service();
+  Datastore localDatastore = helper.options().service();
   ```
+
 3. Run your tests.
 
-4. Stop the local datastore emulator.
-  - If you ran `LocalGcdHelper.java`'s `main` function to start the emulator, run `LocalGcdHelper.java`'s `main` method with arguments `STOP` and (optionally) `--port=<port number>`.  If the port is not supplied, the program will attempt to close the last port started.
-  - If you ran `LocalGcdHelper.start()` to start the emulator, call the `stop()` method on the `LocalGcdHelper` object returned by `LocalGcdHelper.start()`.
+4. Stop the local datastore emulator by calling the `stop()` method, like so:
+  ```java
+  helper.stop();
+  ```
 
 #### On a remote machine
 
-You can test against a remote datastore emulator as well.  To do this, set the `DatastoreOptions` project endpoint to the hostname of the remote machine, like the example below.
+You can test against a remote Datastore emulator as well.  To do this, set the `DatastoreOptions` project endpoint to the hostname of the remote machine, like the example below.
 
   ```java
   DatastoreOptions options = DatastoreOptions.builder()
-      .projectId(PROJECT_ID)
+      .projectId("my-project-id") // must match project ID specified on remote machine
       .host("http://<hostname of machine>:<port>")
+      .authCredentials(AuthCredentials.noAuth())
       .build();
   Datastore localDatastore = options.service();
   ```
 
-Note that the remote datastore must be running before your tests are run.
+We recommend that you start the emulator on the remote machine using the [Google Cloud SDK](https://cloud.google.com/sdk/gcloud/reference/beta/emulators/datastore/) from command line, as shown below:
+
+```
+gcloud beta emulators datastore start --host-port <hostname of machine>:<port>
+```
 
 ### Testing code that uses Storage
 
-Currently, there isn't an emulator for Google Cloud Storage, so an alternative is to create a test project.  `RemoteGcsHelper` contains convenience methods to make setting up and cleaning up the test project easier.  To use this class, follow the steps below:
+Currently, there isn't an emulator for Google Cloud Storage, so an alternative is to create a test project.  `RemoteStorageHelper` contains convenience methods to make setting up and cleaning up the test project easier.  To use this class, follow the steps below:
 
 1. Create a test Google Cloud project.
 
 2. Download a JSON service account credentials file from the Google Developer's Console.  See more about this on the [Google Cloud Platform Storage Authentication page][cloud-platform-storage-authentication]. 
 
-3. Create a `RemoteGcsHelper` object using your project ID and JSON key.
-Here is an example that uses the `RemoteGcsHelper` to create a bucket.
+3. Create a `RemoteStorageHelper` object using your project ID and JSON key.
+Here is an example that uses the `RemoteStorageHelper` to create a bucket.
   ```java
-  RemoteGcsHelper gcsHelper =
-      RemoteGcsHelper.create(PROJECT_ID, new FileInputStream("/path/to/my/JSON/key.json"));
-  Storage storage = gcsHelper.options().service();
-  String bucket = RemoteGcsHelper.generateBucketName();
+  RemoteStorageHelper helper =
+      RemoteStorageHelper.create(PROJECT_ID, new FileInputStream("/path/to/my/JSON/key.json"));
+  Storage storage = helper.options().service();
+  String bucket = RemoteStorageHelper.generateBucketName();
   storage.create(BucketInfo.of(bucket));
   ```
 
@@ -68,7 +77,7 @@ Here is an example that uses the `RemoteGcsHelper` to create a bucket.
 5. Clean up the test project by using `forceDelete` to clear any buckets used.
 Here is an example that clears the bucket created in Step 3 with a timeout of 5 seconds.
   ```java
-  RemoteGcsHelper.forceDelete(storage, bucket, 5, TimeUnit.SECONDS);
+  RemoteStorageHelper.forceDelete(storage, bucket, 5, TimeUnit.SECONDS);
   ```
 
 ### Testing code that uses Resource Manager
@@ -134,4 +143,4 @@ Here is an example that clears the dataset created in Step 3.
   ```
 
 [cloud-platform-storage-authentication]:https://cloud.google.com/storage/docs/authentication?hl=en#service_accounts
-[create-service-account]:https://developers.google.com/identity/protocols/OAuth2ServiceAccount#creatinganaccount
+[create-service-account]:https://developers.google.com/identity/protocols/OAuth2ServiceAccount#creatinganaccount

gcloud-java-bigquery/src/test/java/com/google/gcloud/bigquery/it/ITBigQueryTest.java

@@ -67,7 +67,7 @@
 import com.google.gcloud.storage.BlobInfo;
 import com.google.gcloud.storage.BucketInfo;
 import com.google.gcloud.storage.Storage;
-import com.google.gcloud.storage.testing.RemoteGcsHelper;
+import com.google.gcloud.storage.testing.RemoteStorageHelper;
 
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
@@ -135,7 +135,7 @@ public class ITBigQueryTest {
   private static final String LOAD_FILE = "load.csv";
   private static final String JSON_LOAD_FILE = "load.json";
   private static final String EXTRACT_FILE = "extract.csv";
-  private static final String BUCKET = RemoteGcsHelper.generateBucketName();
+  private static final String BUCKET = RemoteStorageHelper.generateBucketName();
   private static final TableId TABLE_ID = TableId.of(DATASET, "testing_table");
   private static final String CSV_CONTENT = "StringValue1\nStringValue2\n";
   private static final String JSON_CONTENT = "{"
@@ -172,9 +172,9 @@ public class ITBigQueryTest {
   @BeforeClass
   public static void beforeClass() throws InterruptedException {
     RemoteBigQueryHelper bigqueryHelper = RemoteBigQueryHelper.create();
-    RemoteGcsHelper gcsHelper = RemoteGcsHelper.create();
+    RemoteStorageHelper storageHelper = RemoteStorageHelper.create();
     bigquery = bigqueryHelper.options().service();
-    storage = gcsHelper.options().service();
+    storage = storageHelper.options().service();
     storage.create(BucketInfo.of(BUCKET));
     storage.create(BlobInfo.builder(BUCKET, LOAD_FILE).contentType("text/plain").build(),
         CSV_CONTENT.getBytes(StandardCharsets.UTF_8));
@@ -200,7 +200,7 @@ public static void afterClass() throws ExecutionException, InterruptedException
       RemoteBigQueryHelper.forceDelete(bigquery, DATASET);
     }
     if (storage != null) {
-      boolean wasDeleted = RemoteGcsHelper.forceDelete(storage, BUCKET, 10, TimeUnit.SECONDS);
+      boolean wasDeleted = RemoteStorageHelper.forceDelete(storage, BUCKET, 10, TimeUnit.SECONDS);
       if (!wasDeleted && LOG.isLoggable(Level.WARNING)) {
         LOG.log(Level.WARNING, "Deletion of bucket {0} timed out, bucket is not empty", BUCKET);
       }

gcloud-java-core/src/main/java/com/google/gcloud/AuthCredentials.java

@@ -339,7 +339,7 @@ public RestorableState<AuthCredentials> capture() {
   /**
    * A placeholder for credentials to signify that requests sent to the server should not be
    * authenticated. This is typically useful when using the local service emulators, such as
-   * {@code LocalGcdHelper} and {@code LocalResourceManagerHelper}.
+   * {@code LocalDatastoreHelper} and {@code LocalResourceManagerHelper}.
    */
   public static class NoAuthCredentials extends AuthCredentials {
 
@@ -425,7 +425,7 @@ public static ServiceAccountAuthCredentials createFor(String account, PrivateKey
 
   /**
    * Creates a placeholder denoting that no credentials should be used. This is typically useful
-   * when using the local service emulators, such as {@code LocalGcdHelper} and
+   * when using the local service emulators, such as {@code LocalDatastoreHelper} and
    * {@code LocalResourceManagerHelper}.
    */
   public static AuthCredentials noAuth() {