core tests: disambiguate arg 'request' through typing

Both requests.Request and _pytest.FixtureRequest objects are passed to test fixtures as argument 'request'. This hurts readability. Adding typing annotations makes it clear which one is meant.

---

Migrated from D4382 (view on Phabricator)

swh/core/db/pytest_plugin.py

@@ -8,6 +8,7 @@ import logging
 import subprocess
 from typing import Optional, Set, Union
 
+from _pytest.fixtures import FixtureRequest
 import psycopg2
 import pytest
 from pytest_postgresql import factories
@@ -137,7 +138,7 @@ def postgresql_fact(
     no_truncate_tables: Set[str] = {"dbversion"},
 ):
     @pytest.fixture
-    def postgresql_factory(request):
+    def postgresql_factory(request: FixtureRequest):
         """Fixture factory for PostgreSQL.
 
         :param FixtureRequest request: fixture request object