SortOperator extends PhysicalPlan { @Override public boolean hasNext() { return iterator.hasNext(); } SortOperator(
      PhysicalPlan input, Integer count, List<Pair<SortOption, Expression>> sortList); @Override R accept(PhysicalPlanNodeVisitor<R, C> visitor, C context); @Override void open(); @Override List<PhysicalPlan> getChild(); @Override boolean hasNext(); @Override ExprValue next();  }
@Test public void sort_one_field_without_input() { when(inputPlan.hasNext()).thenReturn(false); assertEquals( 0, execute(sort(inputPlan, 1, Pair.of(SortOption.PPL_ASC, ref("response", INTEGER)))).size()); }