fix(emulator): add anonymous credentials for emulator based on env

Author: Spirans

.github/workflows/ci.yml

@@ -30,6 +30,7 @@ jobs:
       run: |
         npm install -g firebase-tools
         firebase emulators:exec --only database --project fake-project-id 'pytest integration/test_db.py'
+        firebase emulators:exec --only storage --project fake-project-id 'pytest integration/test_storage.py --cert tests/data/service_account.json'
 
   lint:
     runs-on: ubuntu-latest

CONTRIBUTING.md

@@ -218,6 +218,7 @@ First, install the Firebase CLI, then run:
 
 ```
 firebase emulators:exec --only database --project fake-project-id 'pytest integration/test_db.py'
+firebase emulators:exec --only storage --project fake-project-id 'pytest integration/test_storage.py --cert tests/data/service_account.json'
 ```
 
 ### Test Coverage

firebase_admin/storage.py

@@ -21,12 +21,14 @@
 # pylint: disable=import-error,no-name-in-module
 try:
     from google.cloud import storage
+    from google.cloud.storage._helpers import STORAGE_EMULATOR_ENV_VAR
 except ImportError:
     raise ImportError('Failed to import the Cloud Storage library for Python. Make sure '
                       'to install the "google-cloud-storage" module.')
 
-from firebase_admin import _utils
+import os
 
+from firebase_admin import _utils
 
 _STORAGE_ATTRIBUTE = '_storage'
 
@@ -61,7 +63,10 @@ def __init__(self, credentials, project, default_bucket):
 
     @classmethod
     def from_app(cls, app):
-        credentials = app.credential.get_credential()
+        if os.getenv(STORAGE_EMULATOR_ENV_VAR) is not None:
+            credentials = _utils.EmulatorAdminCredentials()
+        else:
+            credentials = app.credential.get_credential()
         default_bucket = app.options.get('storageBucket')
         # Specifying project ID is not required, but providing it when available
         # significantly speeds up the initialization of the storage client.