Add direct polygon label QA

backend/tests/test_operator_polygon_label_qa.py

@@ -0,0 +1,22 @@
+from scripts.render_operator_polygon_label_qa import geometry_rings
+
+
+def test_geometry_rings_yields_polygon_exterior_and_hole() -> None:
+    exterior = [[0, 0], [1, 0], [1, 1], [0, 0]]
+    hole = [[0.2, 0.2], [0.4, 0.2], [0.2, 0.2]]
+    assert list(geometry_rings({"type": "Polygon", "coordinates": [exterior, hole]})) == [
+        exterior,
+        hole,
+    ]
+
+
+def test_geometry_rings_flattens_multipolygon_rings() -> None:
+    first = [[0, 0], [1, 0], [0, 0]]
+    second = [[2, 2], [3, 2], [2, 2]]
+    assert list(
+        geometry_rings({"type": "MultiPolygon", "coordinates": [[first], [second]]})
+    ) == [first, second]
+
+
+def test_geometry_rings_ignores_non_polygon_geometry() -> None:
+    assert list(geometry_rings({"type": "Point", "coordinates": [0, 0]})) == []