Free rooms doesn't cause errors but further data verification is necessary

tests/test_free_rooms_action.py

@@ -560,3 +560,166 @@ async def test_closing_season_with_rooms_is_allowed(db_session: AsyncSession):
         db_session,
     )
     assert response.status_code == HttpStatusCode.OK
+
+
+@pytest.mark.asyncio
+async def test_complete_set_with_single_empty_inventory_resets_all_availability(
+    db_session: AsyncSession,
+):
+    """Test the special case: CompleteSet with one empty Inventory element to reset all availability.
+
+    According to AlpineBits spec, to completely reset all room availability information for a hotel,
+    a client can send a CompleteSet request with just one empty Inventory element without any
+    attributes. This is the only exception to the rule that StatusApplicationControl is required.
+    """
+    await insert_test_hotel(db_session)
+    action = make_action()
+
+    # First, add some availability data
+    initial_xml = build_complete_set_xml(
+        daily_inventory("2025-01-01", "2025-01-05", inv_type="DBL", count=10)
+    )
+    await action.handle(
+        "OTA_HotelInvCountNotif:FreeRooms",
+        initial_xml,
+        Version.V2024_10,
+        make_client_info(),
+        db_session,
+    )
+
+    # Verify data was created
+    rows_before = (await db_session.execute(select(RoomAvailability))).scalars().all()
+    assert len(rows_before) == 5
+    inventory_before = (await db_session.execute(select(HotelInventory))).scalars().all()
+    assert len(inventory_before) == 1
+    assert inventory_before[0].source == "FreeRooms"
+
+    # Now send the special reset request with empty Inventory element
+    reset_xml = build_complete_set_xml("<Inventory/>")
+
+    response = await action.handle(
+        "OTA_HotelInvCountNotif:FreeRooms",
+        reset_xml,
+        Version.V2024_10,
+        make_client_info(),
+        db_session,
+    )
+
+    # Should succeed
+    assert response.status_code == HttpStatusCode.OK
+
+    # All availability and FreeRooms-sourced inventory should be cleared
+    rows_after = (await db_session.execute(select(RoomAvailability))).scalars().all()
+    assert len(rows_after) == 0
+    inventory_after = (await db_session.execute(select(HotelInventory))).scalars().all()
+    assert len(inventory_after) == 0
+
+
+@pytest.mark.asyncio
+async def test_delta_with_empty_inventory_is_rejected(db_session: AsyncSession):
+    """Test that empty Inventory is only allowed for CompleteSet, not Delta."""
+    await insert_test_hotel(db_session)
+    action = make_action()
+
+    xml = build_delta_xml("<Inventory/>")
+
+    response = await action.handle(
+        "OTA_HotelInvCountNotif:FreeRooms",
+        xml,
+        Version.V2024_10,
+        make_client_info(),
+        db_session,
+    )
+
+    # Delta requests cannot use empty Inventory
+    assert response.status_code == HttpStatusCode.BAD_REQUEST
+    assert "StatusApplicationControl element is required" in response.xml_content
+
+
+@pytest.mark.asyncio
+async def test_complete_set_with_multiple_empty_inventories_is_rejected(
+    db_session: AsyncSession,
+):
+    """Test that the empty Inventory exception only applies to a single empty Inventory."""
+    await insert_test_hotel(db_session)
+    action = make_action()
+
+    # Multiple empty Inventory elements should not be allowed
+    xml = build_complete_set_xml("<Inventory/><Inventory/>")
+
+    response = await action.handle(
+        "OTA_HotelInvCountNotif:FreeRooms",
+        xml,
+        Version.V2024_10,
+        make_client_info(),
+        db_session,
+    )
+
+    # Should fail because the special case only applies to a single empty Inventory
+    assert response.status_code == HttpStatusCode.BAD_REQUEST
+    assert "StatusApplicationControl element is required" in response.xml_content
+
+
+@pytest.mark.asyncio
+async def test_complete_set_preserves_inventory_from_other_sources(db_session: AsyncSession):
+    """Test that CompleteSet only deletes FreeRooms-sourced inventory, not inventory from other sources."""
+    await insert_test_hotel(db_session)
+    action = make_action()
+
+    # First, add some FreeRooms inventory
+    freerooms_xml = build_complete_set_xml(
+        daily_inventory("2025-01-01", "2025-01-05", inv_type="DBL", count=10)
+    )
+    await action.handle(
+        "OTA_HotelInvCountNotif:FreeRooms",
+        freerooms_xml,
+        Version.V2024_10,
+        make_client_info(),
+        db_session,
+    )
+
+    # Manually add inventory from another source (simulating HotelInventory endpoint)
+    other_inventory = HotelInventory(
+        hotel_id="TESTHOTEL",
+        inv_type_code="SGL",
+        inv_code=None,
+        source="HotelInventory",
+        first_seen=datetime.now(UTC),
+        last_updated=datetime.now(UTC),
+    )
+    db_session.add(other_inventory)
+    await db_session.commit()
+
+    # Verify both inventory items exist
+    inventory_before = (
+        await db_session.execute(select(HotelInventory).order_by(HotelInventory.source))
+    ).scalars().all()
+    assert len(inventory_before) == 2
+    assert inventory_before[0].source == "FreeRooms"
+    assert inventory_before[1].source == "HotelInventory"
+
+    # Send a new CompleteSet with different data
+    new_xml = build_complete_set_xml(
+        daily_inventory("2025-01-01", "2025-01-03", inv_type="TRIPLE", count=5)
+    )
+    response = await action.handle(
+        "OTA_HotelInvCountNotif:FreeRooms",
+        new_xml,
+        Version.V2024_10,
+        make_client_info(),
+        db_session,
+    )
+
+    assert response.status_code == HttpStatusCode.OK
+
+    # Check inventory: FreeRooms inventory should be replaced, but HotelInventory source should remain
+    inventory_after = (
+        await db_session.execute(select(HotelInventory).order_by(HotelInventory.source))
+    ).scalars().all()
+    assert len(inventory_after) == 2
+    # New FreeRooms inventory
+    assert inventory_after[0].source == "FreeRooms"
+    assert inventory_after[0].inv_type_code == "TRIPLE"
+    # Preserved HotelInventory source
+    assert inventory_after[1].source == "HotelInventory"
+    assert inventory_after[1].inv_type_code == "SGL"