From 6e1b18ba33ea6f202d39c13598e0228dd659c7cd Mon Sep 17 00:00:00 2001
From: Thomas Krijnen <t.krijnen@gmail.com>
Date: Mon, 19 Jun 2023 13:48:35 +0200
Subject: [PATCH] #3120 item_id vector test case

---
 .../test/test_create_shape.py                 | 83 +++++++++++++++++++
 1 file changed, 83 insertions(+)
 create mode 100644 src/ifcopenshell-python/test/test_create_shape.py

diff --git a/src/ifcopenshell-python/test/test_create_shape.py b/src/ifcopenshell-python/test/test_create_shape.py
new file mode 100644
index 0000000000..1e087f74b0
--- /dev/null
+++ b/src/ifcopenshell-python/test/test_create_shape.py
@@ -0,0 +1,83 @@
+import ifcopenshell
+import ifcopenshell.api
+import ifcopenshell.geom
+
+import bootstrap
+
+
+class TestAssignObject(bootstrap.IFC4):
+    def test_no_welding_on_distinct_items(self):
+        ifcopenshell.api.run(
+            "root.create_entity", self.file, ifc_class="IfcProject", name="Test"
+        )
+        unit = ifcopenshell.api.run(
+            "unit.add_si_unit", self.file, unit_type="LENGTHUNIT"
+        )
+        ifcopenshell.api.run("unit.assign_unit", self.file, units=[unit])
+        context = ifcopenshell.api.run(
+            "context.add_context", self.file, context_type="Model"
+        )
+        element = ifcopenshell.api.run(
+            "root.create_entity", self.file, ifc_class="IfcWall"
+        )
+
+        def create_extrusion(x, y):
+            points = (
+                (x + 0.0, y + 0.0),
+                (x + 0.0, y + 1.0),
+                (x + 1.0, y + 1.0),
+                (x + 1.0, y + 0.0),
+                (x + 0.0, y + 0.0),
+            )
+            curve = self.file.createIfcPolyline(
+                [self.file.createIfcCartesianPoint(p) for p in points]
+            )
+            extrusion_direction = self.file.createIfcDirection((0.0, 0.0, 1.0))
+            return self.file.createIfcExtrudedAreaSolid(
+                self.file.createIfcArbitraryClosedProfileDef("AREA", None, curve),
+                self.file.createIfcAxis2Placement3D(
+                    self.file.createIfcCartesianPoint((0.0, 0.0, 0.0)),
+                ),
+                extrusion_direction,
+                1.0,
+            )
+
+        extrusions = [create_extrusion(x, 0.0) for x in [0.0, 1.0]]
+        element.Representation = self.file.createIfcProductDefinitionShape(
+            Representations=[
+                self.file.createIfcShapeRepresentation(
+                    context,
+                    context.ContextIdentifier,
+                    "SweptSolid",
+                    extrusions,
+                )
+            ]
+        )
+
+        obj = ifcopenshell.geom.create_shape(
+            ifcopenshell.geom.settings(WELD_VERTICES=True), element
+        )
+
+        # item_ids is a per-triangle array, so we have 12 triangles per cube
+        # even though not documented, the order in representation items should match
+        assert (
+            obj.geometry.item_ids
+            == (extrusions[0].id(),) * 12 + (extrusions[1].id(),) * 12
+        )
+
+        # group the vertices
+        vs = [
+            obj.geometry.verts[i : i + 3] for i in range(0, len(obj.geometry.verts), 3)
+        ]
+
+        # welding should not happen between distinct items so the total number of verts should be 2 times 8
+        assert len(vs) == 16
+
+        # even though there are only 12 unique vertices as the cubes are touching
+        assert len(set(vs)) == 12
+
+
+if __name__ == "__main__":
+    import pytest
+
+    pytest.main(["-vvsx", __file__])