Getting error in converting Json response to java object while writing test cases

Abhishek Mishra :

I am working with an api and using Gson to convert Json response into java object. The code is working fine and I am getting the required results, but when I am writing test cases I am getting a ClassCastException.

GET Call:

String jsonResponse = getData(parameter1,parameter2);//api call
if(!StringUtils.equalsIgnoreCase(jsonResponse, "null"))
{`JSONObject jsonObject = new JSONObject(jsonResponse);`
Gson gson = new Gson();
somejavaObject = gson.fromJson((String) jsonObject.get("data"),
               javaObject.class);
}

POST call:

ObjectMapper mapper = new ObjectMapper();
String objectString = mapper.writeValueAsString(object);
JSONObject request = new JSONObject();
request.put("data", objectString);
request.put("otherData", someValue);
//then POST call

Test case for GET call:

String json = "{\"data\": {\"value1\": {\"v1\": 123, \"v2\": 456}, \"list\": [{\"l1\": 123, \"l2\" :456}]}}";

PowerMockito.doReturn(json).when(spy,"getData",parameters);

The above code is working for the api but failing the test case at the above line and throwing me error:

java.lang.ClassCastException: org.json.JSONObject cannot be cast to java.lang.String

Abhishek :

I found the solution. The problem was that I casted to a wrong type.

somejavaObject = gson.fromJson((String) jsonObject.get("data"), javaObject.class);

I changed the line above to

somejavaObject = gson.fromJson( jsonObject.get("data").toString(), javaObject.class);

and it works now.