refactor: make mock_enqueue_job fixture opt-in instead of autouse

Tests that call POST /api/counter/increment now explicitly request
the mock_enqueue_job fixture. This prevents the mock from masking
issues in other tests that don't need it.

backend/tests/conftest.py

@@ -241,13 +241,15 @@ async def user_no_roles(client_factory):
     }
 
 
-@pytest.fixture(autouse=True)
+@pytest.fixture
 def mock_enqueue_job():
-    """Mock job enqueueing for all tests.
+    """Mock job enqueueing for tests that hit the counter increment endpoint.
 
     pgqueuer requires PostgreSQL-specific features that aren't available
     in the test database setup. We mock the enqueue function to avoid
     connection issues while still testing the counter logic.
+
+    Tests that call POST /api/counter/increment must use this fixture.
     """
     mock = AsyncMock(return_value=1)  # Return a fake job ID
     with patch("routes.counter.enqueue_random_number_job", mock):

backend/tests/test_counter.py

@@ -97,7 +97,7 @@ async def test_get_counter_authenticated(client_factory):
 
 
 @pytest.mark.asyncio
-async def test_increment_counter(client_factory):
+async def test_increment_counter(client_factory, mock_enqueue_job):
     async with client_factory.get_db_session() as db:
         godfather = await create_user_with_roles(
             db, unique_email("gf"), "pass123", [ROLE_REGULAR]
@@ -126,7 +126,7 @@ async def test_increment_counter(client_factory):
 
 
 @pytest.mark.asyncio
-async def test_increment_counter_multiple(client_factory):
+async def test_increment_counter_multiple(client_factory, mock_enqueue_job):
     async with client_factory.get_db_session() as db:
         godfather = await create_user_with_roles(
             db, unique_email("gf"), "pass123", [ROLE_REGULAR]
@@ -157,7 +157,7 @@ async def test_increment_counter_multiple(client_factory):
 
 
 @pytest.mark.asyncio
-async def test_get_counter_after_increment(client_factory):
+async def test_get_counter_after_increment(client_factory, mock_enqueue_job):
     async with client_factory.get_db_session() as db:
         godfather = await create_user_with_roles(
             db, unique_email("gf"), "pass123", [ROLE_REGULAR]
@@ -187,7 +187,7 @@ async def test_get_counter_after_increment(client_factory):
 
 # Counter is shared between users
 @pytest.mark.asyncio
-async def test_counter_shared_between_users(client_factory):
+async def test_counter_shared_between_users(client_factory, mock_enqueue_job):
     # Create godfather and invites for two users
     async with client_factory.get_db_session() as db:
         godfather = await create_user_with_roles(

backend/tests/test_permissions.py

@@ -104,7 +104,7 @@ class TestCounterAccess:
 
     @pytest.mark.asyncio
     async def test_regular_user_can_increment_counter(
-        self, client_factory, regular_user
+        self, client_factory, regular_user, mock_enqueue_job
     ):
         async with client_factory.create(cookies=regular_user["cookies"]) as client:
             response = await client.post("/api/counter/increment")
@@ -484,7 +484,7 @@ class TestAuditRecords:
 
     @pytest.mark.asyncio
     async def test_counter_increment_creates_audit_record(
-        self, client_factory, regular_user, admin_user
+        self, client_factory, regular_user, admin_user, mock_enqueue_job
     ):
         """Verify that counter increments are recorded and visible in audit."""
         # Regular user increments counter