Redesign unittest to be more robust

tests/unittests/tiglWingCell.cpp

@@ -117,6 +117,8 @@ TEST(WingCell, IssueCellsNoOverlap)
 
     ReturnCode tixiRet;
     TiglReturnCode tiglRet;
+    Standard_Real first1, last1, first2, last2;
+    gp_Pnt pntCurve1, pntCurve2;
 
     TiglCPACSConfigurationHandle tiglHandle = -1;
     TixiDocumentHandle tixiHandle = -1;
@@ -133,13 +135,37 @@ TEST(WingCell, IssueCellsNoOverlap)
     TopoDS_Shape cellLoft1 = cell1.GetLoft()->Shape();
 
     auto& cell2 = uid_mgr.ResolveObject<tigl::CCPACSWingCell>(cell2Name.c_str());
-
     TopoDS_Shape cellLoft2 = cell2.GetLoft()->Shape();
-    TopoDS_Shape cellCut = CutShapes(cellLoft1, cellLoft2);
-    TopTools_IndexedMapOfShape faces;
-    TopExp::MapShapes (cellCut, TopAbs_EDGE, faces);
 
-    // Test whether the cut of the two cells is only one line and not an area
-    // Therefore count the edges, must be equal to one
-    ASSERT_EQ(1, faces.Extent());
+    // Take the outermost edge of the first cell and the innermost edge of the second cell which should be compared
+    // If these edges are identical, the cut of the cells is exactely defined by this edge
+    // Hence, the cells have no overlap
+    // In the following, the edges are compared by comparing three points at parameters 0, 0.5 and 1
+    // If the resulting points are pairwise the same (up to tolerance), the edges are the same and the cells do not overlap
+    TopTools_IndexedMapOfShape edges1, edges2;
+    TopExp::MapShapes (cellLoft1, TopAbs_EDGE, edges1);
+    TopExp::MapShapes (cellLoft2, TopAbs_EDGE, edges2);
+
+    TopoDS_Edge edge1 = TopoDS::Edge(edges1(8)); // Since the cell is defined on two segments, it consists of two faces (-> 8 edges)
+    TopoDS_Edge edge2 = TopoDS::Edge(edges2(2));
+    Handle(Geom_BSplineCurve) curve1 = Handle(Geom_BSplineCurve)::DownCast(BRep_Tool::Curve(edge1, first1, last1));
+    Handle(Geom_BSplineCurve) curve2 = Handle(Geom_BSplineCurve)::DownCast(BRep_Tool::Curve(edge2, first2, last2));
+
+    curve1->D0(0., pntCurve1);
+    curve2->D0(0., pntCurve2);
+    ASSERT_NEAR(pntCurve1.X(), pntCurve2.X(), 1e-3);
+    ASSERT_NEAR(pntCurve1.Y(), pntCurve2.Y(), 1e-3);
+    ASSERT_NEAR(pntCurve1.Z(), pntCurve2.Z(), 1e-3);
+
+    curve1->D0(0.5, pntCurve1);
+    curve2->D0(0.5, pntCurve2);
+    ASSERT_NEAR(pntCurve1.X(), pntCurve2.X(), 1e-3);
+    ASSERT_NEAR(pntCurve1.Y(), pntCurve2.Y(), 1e-3);
+    ASSERT_NEAR(pntCurve1.Z(), pntCurve2.Z(), 1e-3);
+
+    curve1->D0(1., pntCurve1);
+    curve2->D0(1., pntCurve2);
+    ASSERT_NEAR(pntCurve1.X(), pntCurve2.X(), 1e-3);
+    ASSERT_NEAR(pntCurve1.Y(), pntCurve2.Y(), 1e-3);
+    ASSERT_NEAR(pntCurve1.Z(), pntCurve2.Z(), 1e-3);
 }