[bugfix][LevelIntersectionIterator] added exception for level>0 because

that case is simply not implemented.

dune/alugrid/common/intersectioniteratorwrapper.hh

@@ -389,7 +389,15 @@ public:
   template <class EntityImp>
   LevelIntersectionIteratorWrapper(const GridImp& grid, const EntityImp & en, int wLevel , bool end )
   : intersection_( IntersectionImp( grid, en, wLevel, end ) )
-  {}
+  {
+    if( wLevel > 0 && grid.conformingRefinement() )
+    {
+      // conceptually the level intersection iterator does not work for
+      // bisection type grids, only on the macro level. Therefore,
+      // an exception is thrown here
+      DUNE_THROW( NotImplemented, "LevelIntersectionIterator does not work for bisection refinement type grids on higher levels!");
+    }
+  }
 
   //! The copy constructor
   LevelIntersectionIteratorWrapper(const ThisType & org)

dune/alugrid/test/CMakeLists.txt

@@ -2,6 +2,7 @@ set(TESTS
   test-alugrid
   test-adaptivity
   test-fromtogridfactory
+  test-iterators
   test-structuredgridfactory
   test-twists
   test-hierarchic
@@ -10,7 +11,6 @@ set(TESTS
   test-gmsh
 )
 
-#  test-iterators
 foreach(TEST ${TESTS})
   dune_add_test(NAME ${TEST} SOURCES ${TEST}.cc LINK_LIBRARIES dunealugrid)
 endforeach()

dune/alugrid/test/test-iterators.cc

@@ -85,8 +85,14 @@ void checkIntersections( GridType& grid )
   auto level_view = grid.levelView(1);
   for (auto && entity : Dune::elements(level_view)) {
     std::cout << "entity " << level_view.indexSet().index(entity) << std::endl;
+    try {
     for (auto&& intersection : Dune::intersections(level_view, entity))
       std::cout << "  intersection " << intersection.indexInInside() << std::endl;
+    }
+    catch ( const Dune::NotImplemented& e )
+    {
+      std::cout << e.what() << std::endl;
+    }
   }
 }