chore: fix linting issues + cleanup

Author: Salakar

src/firebase_functions/private/util.py

@@ -248,7 +248,7 @@ def on_call_check_tokens(request: _Request,) -> _OnCallTokenVerification:
 @_dataclasses.dataclass(frozen=True)
 class FirebaseConfig():
     """
-    A collection of configuration options needed to 
+    A collection of configuration options needed to
     initialize a firebase App.
     """
 
@@ -265,22 +265,22 @@ def firebase_config() -> None | FirebaseConfig:
     config_file = _os.getenv("FIREBASE_CONFIG")
     if not config_file:
         return None
-    if config_file.startswith('{'):
+    if config_file.startswith("{"):
         json_str = config_file
     else:
         # Firebase Tools will always use a JSON blob in prod, but docs
         # explicitly state that the user can set the env to a file:
         # https://firebase.google.com/docs/admin/setup#initialize-without-parameters
         try:
-            with open(config_file, 'r') as json_file:
+            with open(config_file, "r", encoding="utf8") as json_file:
                 json_str = json_file.read()
         except Exception as err:
-            raise ValueError('Unable to read file {}. {}'.format(
-                config_file, err))
+            raise ValueError(
+                f"Unable to read file {config_file}. {err}") from err
     try:
         json_data: dict = _json.loads(json_str)
     except Exception as err:
         raise ValueError(
-            'FIREBASE_CONFIG JSON string "{0}" is not valid json. {1}'.format(
-                json_str, err))
-    return FirebaseConfig(storage_bucket=json_data.get('storageBucket'))
+            f'FIREBASE_CONFIG JSON string "{json_str}" is not valid json. {err}'
+        ) from err
+    return FirebaseConfig(storage_bucket=json_data.get("storageBucket"))

tests/test_util.py

@@ -27,7 +27,7 @@ def test_firebase_config_loads_from_env_json():
     Testing firebase_config can be read from the
     FIREBASE_CONFIG env var as a JSON string.
     """
-    environ["FIREBASE_CONFIG"] = '{"storageBucket": "%s"}' % test_bucket
+    environ["FIREBASE_CONFIG"] = f'{{"storageBucket": "{test_bucket}"}}'
     assert firebase_config().storage_bucket == test_bucket, (
         "Failure, firebase_config did not load from env variable.")
 
@@ -39,4 +39,4 @@ def test_firebase_config_loads_from_env_file():
     """
     environ["FIREBASE_CONFIG"] = test_config_file
     assert firebase_config().storage_bucket == test_bucket, (
-        "Failure, firebase_config did not load from env variable.")
+        "Failure, firebase_config did not load from env variable.")