chore: add pagerduty migrator test + fix linting

tools/migrators/lib/pagerduty/migrate.py

@@ -151,7 +151,9 @@ def migrate() -> None:
                 migrate_notification_rules(user)
                 print(TAB + format_user(user))
     else:
-        print("▶ Skipping migrating user notification rules as MIGRATE_USERS is false...")
+        print(
+            "▶ Skipping migrating user notification rules as MIGRATE_USERS is false..."
+        )
 
     print("▶ Migrating schedules...")
     for schedule in schedules:

tools/migrators/lib/tests/pagerduty/test_migrate.py

@@ -0,0 +1,27 @@
+from unittest.mock import call, patch
+
+from lib.pagerduty.migrate import migrate
+
+
+@patch("lib.pagerduty.migrate.MIGRATE_USERS", False)
+@patch("lib.pagerduty.migrate.APISession")
+@patch("lib.pagerduty.migrate.OnCallAPIClient")
+def test_users_are_skipped_when_migrate_users_is_false(
+    MockOnCallAPIClient, MockAPISession
+):
+    mock_session = MockAPISession.return_value
+    mock_session.list_all.return_value = []
+    mock_oncall_client = MockOnCallAPIClient.return_value
+
+    migrate()
+
+    # Assert no user-related fetching or migration occurs
+    assert mock_session.list_all.call_args_list == [
+        call("schedules", params={"include[]": "schedule_layers", "time_zone": "UTC"}),
+        call("escalation_policies"),
+        call("services", params={"include[]": "integrations"}),
+        call("vendors"),
+        # no user notification rules fetching
+    ]
+
+    mock_oncall_client.list_users_with_notification_rules.assert_not_called()