From a04aebc766676aaaf97c7a0795070bb1588bfd9c Mon Sep 17 00:00:00 2001
From: Guillaume Damiand <guillaume.damiand@liris.cnrs.fr>
Date: Mon, 6 Apr 2020 17:33:24 +0200
Subject: [PATCH] Add a test for shortest cycle non contractible.

---
 .../test/Surface_mesh_topology/CMakeLists.txt |   1 +
 .../test_shortest_cycle_non_contractible.cpp  | 144 ++++++++++++++++++
 2 files changed, 145 insertions(+)
 create mode 100644 Surface_mesh_topology/test/Surface_mesh_topology/test_shortest_cycle_non_contractible.cpp

diff --git a/Surface_mesh_topology/test/Surface_mesh_topology/CMakeLists.txt b/Surface_mesh_topology/test/Surface_mesh_topology/CMakeLists.txt
index 3c0566d65bc..b01a228b068 100644
--- a/Surface_mesh_topology/test/Surface_mesh_topology/CMakeLists.txt
+++ b/Surface_mesh_topology/test/Surface_mesh_topology/CMakeLists.txt
@@ -36,6 +36,7 @@ set(SOURCE_FILES
   test_homotopy.cpp
   test_homotopy_with_polygonal_schema.cpp
   tests_path_on_surface.cpp
+  test_shortest_cycle_non_contractible.cpp
   )
 
 foreach(cppfile ${SOURCE_FILES})
diff --git a/Surface_mesh_topology/test/Surface_mesh_topology/test_shortest_cycle_non_contractible.cpp b/Surface_mesh_topology/test/Surface_mesh_topology/test_shortest_cycle_non_contractible.cpp
new file mode 100644
index 00000000000..48dbef23306
--- /dev/null
+++ b/Surface_mesh_topology/test/Surface_mesh_topology/test_shortest_cycle_non_contractible.cpp
@@ -0,0 +1,144 @@
+#include <CGAL/Simple_cartesian.h>
+#include <CGAL/Surface_mesh.h>
+#include <CGAL/Linear_cell_complex_for_combinatorial_map.h>
+#include <CGAL/Linear_cell_complex_for_generalized_map.h>
+#include <CGAL/Linear_cell_complex_constructors.h>
+#include <CGAL/Polyhedron_3.h>
+#include <iostream>
+#include <fstream>
+#include <CGAL/Curves_on_surface_topology.h>
+#include <CGAL/Path_on_surface.h>
+
+using namespace CGAL::Surface_mesh_topology;
+
+typedef CGAL::Surface_mesh<CGAL::Simple_cartesian<double>::Point_3> SM;
+typedef CGAL::Linear_cell_complex_for_combinatorial_map<2, 3> LCC_CM;
+typedef CGAL::Linear_cell_complex_for_generalized_map<2, 3> LCC_GM;
+typedef CGAL::Polyhedron_3<CGAL::Exact_predicates_inexact_constructions_kernel> Poly;
+
+template<typename LCC>
+void load_lcc(LCC& lcc, const std::string& filename)
+{
+  std::ifstream inp(filename);
+  if (inp.fail())
+  {
+    std::cout<<"Cannot read file '"<<filename<<"'. Exiting program"<<std::endl;
+    exit(EXIT_FAILURE);
+  }
+  CGAL::load_off(lcc, inp);
+}
+
+template<typename SM>
+void load_sm(SM& sm, const std::string& filename)
+{
+  std::ifstream inp(filename);
+  if (inp.fail())
+  {
+    std::cout<<"Cannot read file '"<<filename<<"'. Exiting program"<<std::endl;
+    exit(EXIT_FAILURE);
+  }
+  inp>>sm;
+}
+
+template<typename Mesh>
+bool test_one_data_structure(const Mesh& mesh, std::size_t nbedges, double length)
+{
+  bool res=true;
+  
+  CGAL::Surface_mesh_topology::Euclidean_length_weight_functor<Mesh> wf(mesh);
+  CGAL::Surface_mesh_topology::Curves_on_surface_topology<Mesh>      cst(mesh);
+
+  std::cout<<"."<<std::flush;
+  CGAL::Surface_mesh_topology::Path_on_surface<Mesh> cycle=cst.compute_edgewidth();
+  if (cycle.length()!=nbedges)
+  {
+    std::cout<<"[ERROR]: number of edges for the cycle is not minimal ("<<cycle.length()
+             <<">"<<nbedges<<")."<<std::endl;
+    res=false;
+  }
+  
+  std::cout<<"."<<std::flush;
+  cycle=cst.compute_edgewidth(wf);
+  double l=0.;
+  for (int i=0; i<cycle.length(); ++i) { l+=wf(cycle[i]); }
+  if (l>length)
+  {
+    std::cout<<"[ERROR] length of the cycle is not minimal. ("<<l
+             <<">"<<length<<")."<<std::endl;
+    res=false;
+  }
+  return res;
+}
+
+
+/// Compute edge width for the given mesh (loaded in filename), and test if
+/// the size of the cycle is nbedges for unit weight and the length of the cycle
+/// is smaller than length for Euclidean length weight.
+bool test(const char* filename, std::size_t nbedges, double length)
+{
+  bool res=true;
+  
+  LCC_CM lcc_cm;
+  load_lcc(lcc_cm, filename);
+  if (!test_one_data_structure(lcc_cm, nbedges, length))
+  {
+    std::cout<<"[ERROR] for Linear_cell_complex_for_combinatorial_map."<<std::endl;
+    res=false;
+  }
+  
+  LCC_GM lcc_gm;
+  load_lcc(lcc_gm, filename);
+  if (!test_one_data_structure(lcc_cm, nbedges, length))
+  {
+    std::cout<<"[ERROR] for Linear_cell_complex_for_generalized_map."<<std::endl;
+    res=false;
+  }
+
+  SM sm;
+  load_sm(sm, filename);
+  if (!test_one_data_structure(lcc_cm, nbedges, length))
+  {
+    std::cout<<"[ERROR] for Surface_mesh."<<std::endl;
+    res=false;
+  }
+
+  Poly poly;
+  load_sm(sm, filename);
+  if (!test_one_data_structure(lcc_cm, nbedges, length))
+  {
+    std::cout<<"[ERROR] for Polyhedron_3."<<std::endl;
+    res=false;
+  }
+
+  return res;
+}
+
+int main()
+{
+  bool res=true;
+  std::cout<<"[BEGIN] Test shortest cycle non contractible "<<std::flush;
+
+  if (!test("data/elephant-with-holes.off", 5, 0.0515047))
+  {
+    std::cout<<"[ERROR] for data/elephant-with-holes.off."<<std::endl;
+    res=false;
+  }
+    
+  if (!test("data/obj1.off", 4, 16.2814))
+  { std::cout<<"[ERROR] for data/obj1.off."<<std::endl;
+    res=false;
+  }
+
+  if (!test("data/obj1-with-holes.off", 4, 16.6082))
+  {
+    std::cout<<"[ERROR] for data/elephant-with-holes.off."<<std::endl;
+    res=false;
+  }
+
+  if (!res)
+  { return EXIT_FAILURE; }
+  else
+  { std::cout<<" All tests OK."<<std::endl; }
+  
+  return EXIT_SUCCESS;
+}