Simplify google calendar authentication setup (#67314)

Simplify google calendar authentication to combine some of the cases together, and reduce unecessarily checks. Make the
tests share common authentication setup and reduce use of mocks by introducing a fake for holding on to credentials.
This makes future refactoring simpler, so we don't have to care as much about the interactions with the credentials
storage.

tests/components/google/test_init.py

@@ -53,28 +53,6 @@ async def mock_code_flow(
         yield mock_flow
 
 
-@pytest.fixture
-async def token_scopes() -> list[str]:
-    """Fixture for scopes used during test."""
-    return ["https://www.googleapis.com/auth/calendar"]
-
-
-@pytest.fixture
-async def creds(token_scopes: list[str]) -> OAuth2Credentials:
-    """Fixture that defines creds used in the test."""
-    token_expiry = utcnow() + datetime.timedelta(days=7)
-    return OAuth2Credentials(
-        access_token="ACCESS_TOKEN",
-        client_id="client-id",
-        client_secret="client-secret",
-        refresh_token="REFRESH_TOKEN",
-        token_expiry=token_expiry,
-        token_uri="http://example.com",
-        user_agent="n/a",
-        scopes=token_scopes,
-    )
-
-
 @pytest.fixture
 async def mock_exchange(creds: OAuth2Credentials) -> YieldFixture[Mock]:
     """Fixture for mocking out the exchange for credentials."""
@@ -84,25 +62,6 @@ async def mock_exchange(creds: OAuth2Credentials) -> YieldFixture[Mock]:
         yield mock
 
 
-@pytest.fixture(autouse=True)
-async def mock_token_write(hass: HomeAssistant) -> None:
-    """Fixture to avoid writing token files to disk."""
-    with patch(
-        "homeassistant.components.google.os.path.isfile", return_value=True
-    ), patch("homeassistant.components.google.Storage.put"):
-        yield
-
-
-@pytest.fixture
-async def mock_token_read(
-    hass: HomeAssistant,
-    creds: OAuth2Credentials,
-) -> None:
-    """Fixture to populate an existing token file."""
-    with patch("homeassistant.components.google.Storage.get", return_value=creds):
-        yield
-
-
 @pytest.fixture
 async def calendars_config() -> list[dict[str, Any]]:
     """Fixture for tests to override default calendar configuration."""