Added a test for zipping-based boundary cycle stitching

Polygon_mesh_processing/test/Polygon_mesh_processing/data_stitching/folded_cycle.off

@@ -0,0 +1,59 @@
+# Output of a CGAL tool
+#CBP
+# polyhedral_surface 0
+# halfedges 0
+# triangulated 0
+# non_empty_facets 0
+# terrain 0
+# normalized_to_sphere 0
+# radius 0
+# rounded 0
+# rounded_bits 0
+# ENDCBP
+
+NOFF
+16 16 0
+
+# 16 vertices
+# ------------------------------------------
+
+
+-21.8983 -6.38823 63.7562  0.521628 -0.428916 0.73752
+-21.9152 -6.40483 63.7541  0.42945 -0.529738 0.731403
+-21.9057 -6.32693 63.7553  0.99181 0.00120314 0.127719
+-21.8832 -6.80033 63.7582  0.126127 6.70899e-05 -0.992014
+-21.9216 -6.40893 63.551  0.67402 -0.738711 -0.00201436
+-21.9075 -6.25023 63.7552  -0.995002 -0.0234773 -0.0970594
+-21.8983 -6.38823 63.7562  0.117647 -0.000135467 -0.993055
+-21.9021 -6.75613 63.7558  0.117647 -0.000135467 -0.993055
+-21.9057 -6.32693 63.7553  -0.0977085 -0.99516 -0.010509
+-21.8752 -6.32923 63.7592  -0.126943 -0.00144678 0.991909
+-21.9611 -6.89043 63.7501  0.0910592 0.000407086 -0.995845
+-21.9418 -6.23043 63.7515  -0.109893 -0.00197042 0.993942
+-21.927 -6.32803 63.7529  -0.111856 -0.00218345 0.993722
+-21.9001 -6.39073 63.5534  0.765209 -0.643781 0.00114436
+-21.8874 -6.29763 63.7577  0.341741 -0.938826 0.0426494
+-21.882 -6.36043 63.7583  0.551822 -0.379642 0.742539
+
+# 16 facets
+# ------------------------------------------
+
+3  0 4 13
+3  15 0 13
+3  8 10 5
+3  8 1 0
+3  6 2 14
+3  9 14 2
+3  6 7 10
+3  1 4 0
+3  7 6 14
+3  1 8 12
+3  0 15 2
+3  15 9 2
+3  5 11 8
+3  3 7 14
+3  6 10 8
+3  8 11 12
+
+
+# End of OFF #

Polygon_mesh_processing/test/Polygon_mesh_processing/test_stitching.cpp

@@ -73,6 +73,7 @@ void test_stitch_boundary_cycles()
   test_stitch_boundary_cycles<Mesh>("data_stitching/boundary_cycle.off", 4);
   test_stitch_boundary_cycles<Mesh>("data_stitching/boundary_cycle_2.off", 2);
   test_stitch_boundary_cycles<Mesh>("data_stitching/complex_hole.off", 3);
+  test_stitch_boundary_cycles<Mesh>("data_stitching/folded_cycle.off", 2);
 }
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
@@ -119,9 +120,9 @@ void test_stitch_borders(const char* fname,
   typedef PMP::internal::Halfedges_keeper_with_marked_edge_priority<Marked_edges, Mesh> Keeper;
 
   Marked_edges marks = get(Edge_property_tag(), mesh);
-  int id = 0;
+  int eid = 0;
   for(edge_descriptor e : edges(mesh))
-    put(marks, e, (unconstrained_edge_ids.count(id++) == 0));
+    put(marks, e, (unconstrained_edge_ids.count(eid++) == 0));
 
   Keeper kpr(marks, mesh);