docs: consolidated client creation snippets (GoogleCloudPlatform#1447)

Author: craiglabenz

firestore/src/setup_client_create.php

@@ -30,11 +30,21 @@
 /**
  * Initialize Cloud Firestore with default project ID.
  */
-function setup_client_create()
+function setup_client_create(string $projectId = null)
 {
     // Create the Cloud Firestore client
-    $db = new FirestoreClient();
-    printf('Created Cloud Firestore client with default project ID.' . PHP_EOL);
+    if (empty($projectId)) {
+        // The `projectId` parameter is optional and represents which project the
+        // client will act on behalf of. If not supplied, the client falls back to
+        // the default project inferred from the environment.
+        $db = new FirestoreClient();
+        printf('Created Cloud Firestore client with default project ID.' . PHP_EOL);
+    } else {
+        $db = new FirestoreClient([
+            'projectId' => $projectId,
+        ]);
+        printf('Created Cloud Firestore client with project ID: %s' . PHP_EOL, $projectId);
+    }
 }
 # [END firestore_setup_client_create]
 # [END fs_initialize]

firestore/src/setup_client_create_with_project_id.php

@@ -23,6 +23,8 @@
 
 namespace Google\Cloud\Samples\Firestore;
 
+# TODO(craiglabenz): Remove the `firestore_setup_client_create_with_project_id`
+#                    region tag after consolidating to `firestore_setup_client_create`
 # [START fs_initialize_project_id]
 # [START firestore_setup_client_create_with_project_id]
 use Google\Cloud\Firestore\FirestoreClient;
@@ -42,6 +44,8 @@ function setup_client_create_with_project_id(string $projectId): void
 }
 # [END firestore_setup_client_create_with_project_id]
 # [END fs_initialize_project_id]
+# TODO(craiglabenz): Remove the `firestore_setup_client_create_with_project_id`
+#                    region tag after consolidating to `firestore_setup_client_create`
 
 // The following 2 lines are only needed to run the samples
 require_once __DIR__ . '/../../testing/sample_helpers.php';

firestore/test/firestoreTest.php

@@ -74,13 +74,15 @@ public static function tearDownAfterClass(): void
 
     public function testInitialize()
     {
-        $output = $this->runFirestoreSnippet('setup_client_create', []);
-        $this->assertStringContainsString('Created Cloud Firestore client with default project ID.', $output);
+        $output = self::runFunctionSnippet('setup_client_create', [self::$projectId]);
+        $this->assertStringContainsString('Created Cloud Firestore client with project ID: ', $output);
     }
 
     public function testInitializeProjectId()
     {
-        $output = $this->runFirestoreSnippet('setup_client_create_with_project_id');
+        # The lack of a second parameter implies that a non-empty projectId is
+        # supplied to the snippet's function.
+        $output = $this->runFirestoreSnippet('setup_client_create', [self::$projectId]);
         $this->assertStringContainsString('Created Cloud Firestore client with project ID:', $output);
     }