Defines the is_forward_iterable collection type trait.

namespace boost {
  namespace unit_test {
    template<typename T, 
             bool is_forward_iterable = is_forward_iterable<T>::value> 
      struct bt_iterator_traits;

    template<typename T, std::size_t N> struct bt_iterator_traits<T [N], true>;
    template<typename T> struct bt_iterator_traits<T, true>;

    template<typename T> struct is_container_forward_iterable;
    template<typename T> struct is_forward_iterable;
  }
}