String json = plan1.unparse(c.getMapper().writer());
System.out.println(json);
PhysicalPlan plan2 = reader.readPhysicalPlan(json);
System.out.println("++++++++");
System.out.println(plan2.unparse(c.getMapper().writer()));
PhysicalOperator root = plan2.getSortedOperators(false).iterator().next();
assertEquals(0, root.getOperatorId());
PhysicalOperator o1 = root.iterator().next();
assertEquals(1, o1.getOperatorId());