void test_to_lookuptable() {
    LookupTable* lt;
    Object* key = Fixnum::from(1);
    Object* val = Fixnum::from(2);

    tbl->put(state, 2, key);
    tbl->put(state, 3, val);
    lt = tbl->to_lookuptable(state);

    TS_ASSERT_EQUALS(lt->fetch(state, key), val);
  }