test(storage): add comprehensive file operation tests

packages/dart_firebase_admin/example/lib/storage_example.dart

@@ -1,6 +1,5 @@
 import 'dart:convert';
 import 'package:dart_firebase_admin/dart_firebase_admin.dart';
-import 'package:dart_firebase_admin/storage.dart';
 import 'package:googleapis_storage/googleapis_storage.dart' hide Storage;
 
 Future<void> storageExample(FirebaseApp admin) async {
@@ -14,21 +13,35 @@ Future<void> storageExample(FirebaseApp admin) async {
 Future<void> basicExample(FirebaseApp admin) async {
   print('> Basic Storage usage...\n');
 
-  final storage = Storage(admin);
+  try {
+    final storage = admin.storage();
 
-  final bucket = storage.bucket('dart-firebase-admin.firebasestorage.app');
+    final bucket = storage.bucket('dart-firebase-admin.firebasestorage.app');
+    print('> Using bucket: ${bucket.id}\n');
 
-  final file = bucket.file('foo.txt');
+    final file = bucket.file('foo.txt');
+    print('> File: ${file.name}\n');
+
+    const fileContent = 'Hello from basicExample() in storage_example.dart';
+    print('> Uploading file "${file.name}" to Storage...\n');
+    await file.save(fileContent);
+    print('> ✓ File uploaded successfully!\n');
 
-  await file.delete();
+    print('> Deleting file "${file.name}"...\n');
+    await file.delete();
+    print('> ✓ File deleted successfully!\n');
+  } catch (e, stackTrace) {
+    print('> ✗ Error: $e\n');
+    print('> Stack trace: $stackTrace\n');
+  }
 }
 
 Future<void> signedUrlExample(FirebaseApp admin) async {
   print('> Signed URL Storage usage...\n');
 
   String? url;
   try {
-    final storage = Storage(admin);
+    final storage = admin.storage();
 
     final bucket = storage.bucket('dart-firebase-admin.firebasestorage.app');
     print('> Using bucket: ${bucket.id}\n');

packages/dart_firebase_admin/example/run_with_emulator.sh

@@ -4,6 +4,7 @@
 export FIRESTORE_EMULATOR_HOST=localhost:8080
 export FIREBASE_AUTH_EMULATOR_HOST=localhost:9099
 export CLOUD_TASKS_EMULATOR_HOST=localhost:9499
+export FIREBASE_STORAGE_EMULATOR_HOST=localhost:9199
 export GOOGLE_CLOUD_PROJECT=dart-firebase-admin
 
 # Run the example

packages/dart_firebase_admin/firebase.json

@@ -15,7 +15,10 @@
     "ui": {
       "enabled": true
     },
-    "singleProjectMode": true
+    "singleProjectMode": true,
+    "storage": {
+      "port": 9199
+    }
   },
   "functions": [
     {
@@ -28,5 +31,8 @@
         "*.local"
       ]
     }
-  ]
+  ],
+  "storage": {
+    "rules": "storage.rules"
+  }
 }

packages/dart_firebase_admin/lib/src/app.dart

@@ -21,6 +21,7 @@ import '../firestore.dart';
 import '../functions.dart';
 import '../messaging.dart';
 import '../security_rules.dart';
+import '../storage.dart';
 
 part 'app/app_exception.dart';
 part 'app/app_options.dart';

packages/dart_firebase_admin/lib/src/app/environment.dart

@@ -40,6 +40,12 @@ abstract class Environment {
   /// Format: `host:port` (e.g., `127.0.0.1:9499`)
   static const cloudTasksEmulatorHost = 'CLOUD_TASKS_EMULATOR_HOST';
 
+  /// Firebase Storage Emulator host address.
+  ///
+  /// When set, Storage service automatically connects to the emulator instead of production.
+  /// Format: `host:port` (e.g., `localhost:9199`)
+  static const firebaseStorageEmulatorHost = 'FIREBASE_STORAGE_EMULATOR_HOST';
+
   /// Checks if the Firestore emulator is enabled via environment variable.
   ///
   /// Returns `true` if [firestoreEmulatorHost] is set in the environment.
@@ -87,4 +93,71 @@ abstract class Environment {
         Zone.current[envSymbol] as Map<String, String>? ?? Platform.environment;
     return env[cloudTasksEmulatorHost] != null;
   }
+
+  /// Checks if the Storage emulator is enabled via environment variable.
+  ///
+  /// Returns `true` if [firebaseStorageEmulatorHost] is set in the environment.
+  ///
+  /// Example:
+  /// ```dart
+  /// if (Environment.isStorageEmulatorEnabled()) {
+  ///   print('Using Storage emulator');
+  /// }
+  /// ```
+  static bool isStorageEmulatorEnabled() {
+    final env =
+        Zone.current[envSymbol] as Map<String, String>? ?? Platform.environment;
+    return env[firebaseStorageEmulatorHost] != null;
+  }
+
+  /// Gets the Storage emulator host from environment variables.
+  ///
+  /// Returns the host:port string if set, otherwise null.
+  ///
+  /// Example:
+  /// ```dart
+  /// final host = Environment.getStorageEmulatorHost();
+  /// if (host != null) {
+  ///   print('Storage emulator at $host');
+  /// }
+  /// ```
+  static String? getStorageEmulatorHost() {
+    final env =
+        Zone.current[envSymbol] as Map<String, String>? ?? Platform.environment;
+    return env[firebaseStorageEmulatorHost];
+  }
+
+  /// Gets the Auth emulator host from environment variables.
+  ///
+  /// Returns the host:port string if set, otherwise null.
+  ///
+  /// Example:
+  /// ```dart
+  /// final host = Environment.getAuthEmulatorHost();
+  /// if (host != null) {
+  ///   print('Auth emulator at $host');
+  /// }
+  /// ```
+  static String? getAuthEmulatorHost() {
+    final env =
+        Zone.current[envSymbol] as Map<String, String>? ?? Platform.environment;
+    return env[firebaseAuthEmulatorHost];
+  }
+
+  /// Gets the Cloud Tasks emulator host from environment variables.
+  ///
+  /// Returns the host:port string if set, otherwise null.
+  ///
+  /// Example:
+  /// ```dart
+  /// final host = Environment.getCloudTasksEmulatorHost();
+  /// if (host != null) {
+  ///   print('Tasks emulator at $host');
+  /// }
+  /// ```
+  static String? getCloudTasksEmulatorHost() {
+    final env =
+        Zone.current[envSymbol] as Map<String, String>? ?? Platform.environment;
+    return env[cloudTasksEmulatorHost];
+  }
 }

packages/dart_firebase_admin/lib/src/app/firebase_app.dart

@@ -192,6 +192,11 @@ class FirebaseApp {
   /// Returns a cached instance if one exists, otherwise creates a new one.
   Functions functions() => Functions.internal(this);
 
+  /// Gets the Storage service instance for this app.
+  ///
+  /// Returns a cached instance if one exists, otherwise creates a new one.
+  Storage storage() => Storage.internal(this);
+
   /// Closes this app and cleans up all associated resources.
   ///
   /// This method:

packages/dart_firebase_admin/lib/src/app/firebase_service.dart

@@ -7,7 +7,8 @@ enum FirebaseServiceType {
   firestore(name: 'firestore'),
   messaging(name: 'messaging'),
   securityRules(name: 'security-rules'),
-  functions(name: 'functions');
+  functions(name: 'functions'),
+  storage(name: 'storage');
 
   const FirebaseServiceType({required this.name});
 

packages/dart_firebase_admin/lib/src/auth.dart

@@ -1,8 +1,6 @@
 import 'dart:async';
 import 'dart:convert';
-import 'dart:io';
 import 'dart:typed_data';
-
 import 'package:collection/collection.dart';
 import 'package:dart_jsonwebtoken/dart_jsonwebtoken.dart' as dart_jsonwebtoken;
 import 'package:googleapis/identitytoolkit/v1.dart' as auth1;

packages/dart_firebase_admin/lib/src/auth/auth_http_client.dart

@@ -10,9 +10,7 @@ class AuthHttpClient {
   /// When [Environment.firebaseAuthEmulatorHost] is set, routes requests to
   /// the local Auth emulator. Otherwise, uses production Auth API.
   Uri get _authApiHost {
-    final env =
-        Zone.current[envSymbol] as Map<String, String>? ?? Platform.environment;
-    final emulatorHost = env[Environment.firebaseAuthEmulatorHost];
+    final emulatorHost = Environment.getAuthEmulatorHost();
 
     if (emulatorHost != null) {
       return Uri.http(emulatorHost, 'identitytoolkit.googleapis.com/');

packages/dart_firebase_admin/lib/src/functions/functions.dart

@@ -1,7 +1,5 @@
 import 'dart:async';
 import 'dart:convert';
-import 'dart:io';
-
 import 'package:googleapis/cloudtasks/v2.dart' as tasks2;
 import 'package:googleapis_auth/auth_io.dart' as googleapis_auth;
 import 'package:googleapis_auth_utils/googleapis_auth_utils.dart';

packages/dart_firebase_admin/lib/src/functions/functions_http_client.dart

@@ -14,10 +14,10 @@ class FunctionsHttpClient {
   /// Returns the host:port string (e.g., "localhost:9499") if the
   /// CLOUD_TASKS_EMULATOR_HOST environment variable is set.
   String? get _cloudTasksEmulatorHost {
-    final env =
-        Zone.current[envSymbol] as Map<String, String>? ?? Platform.environment;
-    final host = env[Environment.cloudTasksEmulatorHost];
-    return (host != null && host.isNotEmpty) ? host : null;
+    final emulatorHost = Environment.getCloudTasksEmulatorHost();
+    return (emulatorHost != null && emulatorHost.isNotEmpty)
+        ? emulatorHost
+        : null;
   }
 
   /// Lazy-initialized HTTP client that's cached for reuse.

packages/dart_firebase_admin/lib/src/storage/storage.dart

@@ -0,0 +1,62 @@
+import 'package:googleapis_storage/googleapis_storage.dart'
+    as googleapis_storage;
+import 'package:meta/meta.dart';
+import '../app.dart';
+
+class Storage implements FirebaseService {
+  /// Internal constructor
+  Storage._(this.app) {
+    String? apiEndpoint;
+    final isEmulator = Environment.isStorageEmulatorEnabled();
+
+    if (isEmulator) {
+      final emulatorHost = Environment.getStorageEmulatorHost()!;
+
+      if (RegExp('https?://').hasMatch(emulatorHost)) {
+        throw FirebaseAppException(
+          AppErrorCode.failedPrecondition,
+          'FIREBASE_STORAGE_EMULATOR_HOST should not contain a protocol (http or https).',
+        );
+      }
+      apiEndpoint = 'http://$emulatorHost';
+    }
+
+    _delegate = googleapis_storage.Storage(
+      googleapis_storage.StorageOptions(
+        authClient: isEmulator ? null : app.client,
+        apiEndpoint: apiEndpoint,
+        useAuthWithCustomEndpoint: false,
+      ),
+    );
+  }
+
+  /// Factory constructor that ensures singleton per app.
+  @internal
+  factory Storage.internal(FirebaseApp app) {
+    return app.getOrInitService(FirebaseServiceType.storage.name, Storage._);
+  }
+
+  @override
+  final FirebaseApp app;
+
+  late final googleapis_storage.Storage _delegate;
+
+  googleapis_storage.Bucket bucket(String? name) {
+    final bucketName = name ?? app.options.storageBucket;
+    if (bucketName == null || bucketName.isEmpty) {
+      throw FirebaseAppException(
+        AppErrorCode.failedPrecondition,
+        'Bucket name not specified or invalid. Specify a valid bucket name via the '
+        'storageBucket option when initializing the app, or specify the bucket name '
+        'explicitly when calling the bucket() method.',
+      );
+    }
+
+    return _delegate.bucket(bucketName);
+  }
+
+  @override
+  Future<void> delete() async {
+    await _delegate.terminate();
+  }
+}

packages/dart_firebase_admin/lib/storage.dart

@@ -1 +1 @@
-export 'src/storage.dart';
+export 'src/storage/storage.dart';

packages/dart_firebase_admin/storage.rules

@@ -0,0 +1,12 @@
+rules_version = '2';
+
+// Craft rules based on data in your Firestore database
+// allow write: if firestore.get(
+//    /databases/(default)/documents/users/$(request.auth.uid)).data.isAdmin;
+service firebase.storage {
+  match /b/{bucket}/o {
+    match /{allPaths=**} {
+      allow read, write: if false;
+    }
+  }
+}