Mockito mock is giving null for given test cases - spring-boot

Question

I am using the SpringRunner to run the Junit mockito test case , below is the class , i was trying to write the test case , but getting null object
public class AccountManager {
public String getToken() throws Exception {
#Autowired
RestClient restClient;
String auth = apiUserPrefix + apiUserName + BatchJobConstants.COLON + apiUserPassword;
byte[] encodedAuth = Base64.encodeBase64(
auth.getBytes(StandardCharsets.UTF_8));
String authHeader = BatchJobConstants.BASIC_SPACE + new String(encodedAuth);
String token= null;
MultiValueMap<String, String> data = new LinkedMultiValueMap<>();
data.add("grant_type", "client_credential");
String accManagerUrl = accManagerHost+":"+accManagerPort+"/"+accManagerResPath;
RestResponseObject responseObject = null;
try {
responseObject = restClient.execute(accManagerUrl, HttpMethod.POST, data, String.class, authHeader);
if (responseObject != null && responseObject.getPayload() != null && responseObject.getStatusCode() == HttpStatus.OK) {
JsonElement responseJson = (JsonElement) responseObject.getPayload();
if (responseJson.isJsonObject()) {
token= responseJson.getAsJsonObject().get(BatchJobConstants.ACCESS_TOKEN).getAsString();
}catch(RunTimeException e) {
//e
}
return token;
}
//Junit test case
#RunWith(SpringRunner.class)
public class AccountManagerTest {
#InjectMocks
AccountManager accountManager;
#Mock
RestClient restClient;
#Test
public void getTokenAccMgrSucess() throws Exception {
RestResponseObject restResponseObject = Mockito.mock(RestResponseObject.class);
Mockito.when(restClient.execute(Mockito.anyString(), Mockito.any(HttpMethod.class),
Mockito.anyString(), Mockito.eq(String.class), Mockito.anyString())).thenReturn(restResponseObject);
String token = accountManagerTokenProvider.getToken();
Assert.assertEquals("Token value {} ", null, token);
}
}
But still the below code return null value even after mocking this, can you please help how to mock this.
responseObject = restClient.execute(accManagerUrl, HttpMethod.POST, data, String.class, authHeader);
Note: Only Mockito needs to use no powermockito

Answer 1

For Autowired fields you not only have to mock it but should bind the mocked class to the spring context. You have two options :
1. Mark the mocked class as primary bean
#Configuration
public class TestConfiguration {
#Bean
#Primary
public RestClient restClient() {
return Mockito.mock(RestClient.class);
}
}
2.Use #MockBean annotation
#MockBean
RestClient restClient;
More on this :
https://www.baeldung.com/injecting-mocks-in-spring
https://www.baeldung.com/java-spring-mockito-mock-mockbean

Answer 2

Finally worked with mockito only just user any() instead of anyString(), since the Object is not matching with string only
Mockito.when(restClient.execute(Mockito.any(), Mockito.any(HttpMethod.class),
Mockito.any(), Mockito.eq(String.class), Mockito.any())).thenReturn(restResponseObject);