diff --git a/datatypes/magicplan/domain/tests/test_mapper.py b/datatypes/magicplan/domain/tests/test_mapper.py
index 09e8aa28..85467267 100644
--- a/datatypes/magicplan/domain/tests/test_mapper.py
+++ b/datatypes/magicplan/domain/tests/test_mapper.py
@@ -254,6 +254,14 @@ def test_window_with_no_custom_fields_has_no_ventilation() -> None:
     assert window.ventilation is None
 
 
+def test_doorglass_is_classified_as_window(plan_new: Plan) -> None:
+    # Living/Dining Room (floor 0, room 1) has one doorglass wall item.
+    # It must appear in room.windows, not room.doors.
+    room = plan_new.floors[0].rooms[1]
+
+    assert "doorglass" in [w.opening_type for w in room.windows]
+
+
 def test_toilet_door_has_ventilation_undercut(plan_new: Plan) -> None:
     # Toilet is floor 0 room 2; its doorhinged has Door Undercut (mm) = 70
     toilet_doors = plan_new.floors[0].rooms[2].doors