### Question:
Decision { public String toJsonString() throws JsonProcessingException { return ObjectMapperProvider.get().writeValueAsString(this); }  String toJsonString(); static Decision fromJsonString(String json);  }### Answer:
@Test public void shouldSerializeToJson() throws JsonProcessingException { LocalDateTime now = LocalDateTime.now().plusNanos(1); Request request = new Request( "user1", "manager1", now, "Proszę o urlop"); Decision d = new Decision( "manager1", request, now, Decision.DecisionResult.ACCEPTED); Assert.assertEquals( "{" + "\"managerId\":\"manager1\"," + "\"request\":" + request.toJsonString() + ",\"decisionTime\":\"" + now.toString() + "\"," + "\"decisionResult\":\"ACCEPTED\"" + "}", ObjectMapperProvider.get().writeValueAsString(d) ); }