diff --git a/backend/magic_plan/tests/test_audit_script.py b/backend/magic_plan/tests/test_audit_script.py
index e41ac0d3..5bf14596 100644
--- a/backend/magic_plan/tests/test_audit_script.py
+++ b/backend/magic_plan/tests/test_audit_script.py
@@ -2,6 +2,40 @@ from datatypes.magicplan.domain.models import Door, Floor, Plan, Room, Window
 from backend.magic_plan.audit_script import AuditRow, _build_rows
 
 
+def test_build_rows_opening_and_trickle_vent_fields_are_none() -> None:
+    # Arrange — plan with one window so opening/trickle_vent fields are exercised
+    plan = Plan(
+        uid="x",
+        name=None,
+        floors=[
+            Floor(level=0, name=None, rooms=[
+                Room(
+                    name="Living Room",
+                    width_m=3.0,
+                    length_m=4.0,
+                    area_m2=12.0,
+                    windows=[Window(width_m=1.0, height_m=1.0, area_m2=1.0, opening_type="side_hung")],
+                ),
+            ]),
+        ],
+    )
+
+    # Act
+    rows = _build_rows(plan)
+
+    # Assert — all new forward-compatible fields default to None
+    data_row = next(r for r in rows if r.window_label is not None)
+    assert data_row.opening_count is None
+    assert data_row.opening_width_m is None
+    assert data_row.opening_height_m is None
+    assert data_row.opening_total_area_m2 is None
+    assert data_row.trickle_vent_blocked is None
+    assert data_row.trickle_vent_pictured is None
+    assert data_row.trickle_vent_effective_area is None
+    assert data_row.trickle_vent_count is None
+    assert data_row.trickle_vent_total_effective_area is None
+
+
 def test_build_rows_empty_plan_returns_empty_list() -> None:
     # Arrange
     plan = Plan(uid="x", name=None, floors=[])