add tests for occ identifications

tests/pytest/test_occ_identifications.py

@@ -0,0 +1,76 @@
+import pytest
+
+from netgen.meshing import IdentificationType
+idtype = IdentificationType.CLOSESURFACES
+
+def test_two_boxes():
+    occ = pytest.importorskip("netgen.occ")
+    inner = occ.Box((0,0,0), (1,1,1))
+    trafo = occ.gp_Trsf().Scale(inner.center, 1.1)
+    outer = trafo(inner)
+
+    inner.Identify(outer, "", idtype, trafo)
+    shape = occ.Glue([outer-inner, inner])
+
+    geo = occ.OCCGeometry(shape)
+    mesh = geo.GenerateMesh(maxh=0.3)
+    have_prisms = False
+
+    for el in mesh.Elements3D():
+        if len(el.vertices)==6:
+            have_prisms = True
+            break
+
+    assert have_prisms
+
+def test_two_circles():
+    occ = pytest.importorskip("netgen.occ")
+    circ1 = occ.WorkPlane().Circle(1).Face()
+    trafo = occ.gp_Trsf().Scale(circ1.center, 1.1)
+
+    circ2 = trafo(circ1)
+    circ1.edges[0].Identify(circ2.edges[0], "", idtype, trafo)
+    circ2 -= circ1
+    shape = occ.Glue([circ1, circ2])
+
+    geo = occ.OCCGeometry(shape, 2)
+    mesh = geo.GenerateMesh(maxh=0.2)
+    have_quads = False
+
+    for el in mesh.Elements2D():
+        if len(el.vertices)==4:
+            have_quads = True
+            break
+
+    assert have_quads
+
+def test_cut_identified_face():
+    occ = pytest.importorskip("netgen.occ")
+    from netgen.occ import Z, Box, Cylinder, Glue, OCCGeometry
+    box = Box((-1,-1,0), (1,1,1))
+    cyl = Cylinder( (0,0,0), Z, 0.5, 1 )
+
+    box.faces.Min(Z).Identify(box.faces.Max(Z), "", idtype)
+    shape = Glue([cyl, box])
+    geo = OCCGeometry(shape)
+    mesh = geo.GenerateMesh(maxh=0.5)
+
+    for el in mesh.Elements3D():
+        assert len(el.vertices)==6
+
+def test_identify_multiple_faces():
+    occ = pytest.importorskip("netgen.occ")
+    from netgen.occ import Z, Box, Cylinder, Glue, OCCGeometry, gp_Trsf
+    box = Box((-1,-1,0), (1,1,1))
+    cyl = Cylinder( (0,0,0), Z, 0.5, 1 )
+
+    shape = Glue([box, cyl])
+    bot_faces = shape.faces[Z < 0.1]
+    top_faces = shape.faces[Z > 0.1]
+    bot_faces.Identify(top_faces, "", idtype, gp_Trsf.Translation((0,0,1)))
+
+    geo = OCCGeometry(shape)
+    mesh = geo.GenerateMesh(maxh=0.3)
+
+    for el in mesh.Elements3D():
+        assert len(el.vertices)==6