- Fixed PolyConnectivity is_collapse_ok, missing some configurations (Thanks...

- Fixed PolyConnectivity is_collapse_ok, missing some configurations (Thanks to Simon Flöry for the patch)

src/Unittests/unittests_polymesh_collapse.cc

+#include <gtest/gtest.h>
+#include <Unittests/unittests_common.hh>
+
+#include <iostream>
+
+namespace {
+
+class OpenMeshCollapsePoly : public OpenMeshBasePoly {
+
+    protected:
+
+        // This function is called before each test is run
+        virtual void SetUp() {
+        }
+
+        // This function is called after all tests are through
+        virtual void TearDown() {
+
+            // Do some final stuff with the member data here...
+        }
+
+    // Member already defined in OpenMeshBase
+    //Mesh mesh_;  
+};
+
+/*
+ * ====================================================================
+ * Define tests below
+ * ====================================================================
+ */
+
+
+
+
+/*
+ * This code tests is_collapse_ok on a double sided triangle. The
+ * test mesh comprises three vertices, that are connected to form two 
+ * triangles of opposite orientation. All halfedges should be non collapsable.
+ */
+TEST_F(OpenMeshCollapsePoly, CheckCollapseOkDoublesidedTriangle) {
+
+  mesh_.clear();
+
+  Mesh::VertexHandle vh0 = mesh_.add_vertex(Mesh::Point(0,0,0));
+  Mesh::VertexHandle vh1 = mesh_.add_vertex(Mesh::Point(1,0,0));
+  Mesh::VertexHandle vh2 = mesh_.add_vertex(Mesh::Point(1,1,0));
+  mesh_.add_face(vh0, vh1, vh2);
+  mesh_.add_face(vh0, vh2, vh1);
+
+
+
+  mesh_.request_vertex_status();
+  mesh_.request_face_status();
+  mesh_.request_edge_status();
+
+  int collapsable = 0;
+
+  for ( const auto hh : mesh_.all_halfedges() )
+  {
+    if (mesh_.is_collapse_ok(hh) )
+      collapsable++;
+  }
+
+
+  EXPECT_EQ(collapsable,0) << "No collapse should be ok when we have only a double sided Triangle";
+}
+
+
+
+}