Mocking an autowired field using mockito gives null response in rest call - rest

Question

I am using spring boot and mockito. I have autowired one class i.e, BDSRequest and in Junit Test class, i have used #Spy and #InjectMocks annotations. but while calling rest services in Junits, i am getting response (bdsCustomerHoldings) as null and assertion is failing. How to test this rest call with out mocking rest template like mockito.when(restTemplate.postForObject(Constants.BDS_REST_URL, bdsRequest,
BDSCustomerHoldings.class) ?
class BDSRestCall
{
#Autowired
BDSRequest bdsRequest;
public BDSCustomerHoldings getBDSCustomerInfo(String channelId, String customerId, String cinSuffix,
String countryCode) {
logger.info("prepareRequestForBDS");
Header header = new Header();
header.setMsgId(RandomStringUtils.randomAlphanumeric(20));
header.setChannelId(channelId);
header.setCountryCode(countryCode);
header.setRecordTimeStamp(DateTimeFormatter.ofPattern(Constants.DATE_FORMATTER).format(LocalDateTime.now()));
TxnRequest txnRequest = new TxnRequest();
txnRequest.setIdDoc(customerId);
txnRequest.setIdDocSuffix(cinSuffix);
txnRequest.setIdDoctype("");
txnRequest.setInsurerCode("");
bdsRequest.setHeader(header);
bdsRequest.setTxnRequest(txnRequest);
logger.info("BDS request " + bdsRequest);
BDSCustomerHoldings bdsResponse = restTemplate.postForObject(Constants.BDS_REST_URL, bdsRequest,
BDSCustomerHoldings.class);
logger.info("BDS Response : " + bdsResponse);
return bdsResponse;
}
}
Junit:
#RunWith(MockitoJUnitRunner.class)
class BDSRestCallTest
{
#InjectMocks
private BDSRestCall bdsRestCall;
#Mock
private RestTemplate restTemplate;
#Spy
private BDSRequest bdsRequest;
#Test
public void getBDSCustomerInfoExceptionTest() {
BDSCustomerHoldings bdsCustomerHoldings = bdsRestCall.getBDSCustomerInfo("SG", "S9718016D",
"00", "SG");
System.out.println("response is " + bdsCustomerHoldings);
assertNotNull("response is not null", bdsCustomerHoldings);
}
}

Answer 1

As we are using #RunWith(MockitoJUnitRunner.class), then we should use mocking the response of restTemplate like below
Mockito.when(restTemplate.postForObject(Mockito.anyString(), bdsRequest, BDSCustomerInsuranceHoldings.class)).thenReturn(sampleBDSCustomerInsuranceHoldings());
Then it will give mock response.