
void reset_undo_accounting()
{
  last_undo_stack_height= um->get_undo_stack().size();
  last_redo_stack_height= um->get_redo_stack().size();
}


void check_only_one_undo_added_(const std::string &loc)
{
  ++last_undo_stack_height;
  ensure_equals(loc+": added 1 undo action", um->get_undo_stack().size(), last_undo_stack_height);

  // adding new stuff to the undo stack will clear the redo stack
  last_redo_stack_height= um->get_redo_stack().size();
}
#define check_only_one_undo_added() check_only_one_undo_added_(G_STRINGIFY(__LINE__))


// helper member functions
void check_undo_(const std::string &loc)
{
  ensure_equals(loc+":undo stack size", um->get_undo_stack().size(), last_undo_stack_height);
  ensure_equals(loc+":redo stack size", um->get_redo_stack().size(), last_redo_stack_height);

  // check that the latest undo action has a description
  ensure(loc+":undo action description is set", um->get_action_description() != "");

  // perform undo
  um->undo();

  --last_undo_stack_height;
  // redo stack should grow by 1 and undo shrink by 1
  ensure_equals(loc+":redo stack size after undo", um->get_redo_stack().size(), last_redo_stack_height+1);
  ensure_equals(loc+":undo stack size after undo", um->get_undo_stack().size(), last_undo_stack_height);

  last_redo_stack_height= um->get_redo_stack().size();
}
#define check_undo() check_undo_(G_STRINGIFY(__LINE__))



void check_redo_(const std::string &loc)
{
  // make sure that the undo/redo stack has the expected size
  ensure_equals(loc+":undo stack size", um->get_undo_stack().size(), last_undo_stack_height);
  ensure_equals(loc+":redo stack size", um->get_redo_stack().size(), last_redo_stack_height);

  // perform redo
  um->redo();

  ++last_undo_stack_height;
  ensure_equals(loc+":redo stack size after redo", um->get_redo_stack().size(), last_redo_stack_height-1);
  ensure_equals(loc+":undo stack size after redo", um->get_undo_stack().size(), last_undo_stack_height);

  last_redo_stack_height= um->get_redo_stack().size();
}
#define check_redo() check_redo_(G_STRINGIFY(__LINE__))

