Mock not initiated on Static method - junit

Question

I am facing issues in mocking static method.
Below is my code where I am calling a static method
public class GetAllBatches {
public HttpResponseMessage run(
#HttpTrigger(route = "v1/batches",
name = "request",
methods = {HttpMethod.GET},
authLevel = AuthorizationLevel.ANONYMOUS)
HttpRequestMessage<String> request,
final ExecutionContext context){
context.getLogger().info("List batches Called");
String apiResponse ;
String connector = request.getQueryParameters().getOrDefault("connector", "");
try{
BatchesController batchesController = BatchesController.getInstance();
apiResponse = new Gson().toJson(batchesController.getBatches(connector));
}
}
}
BatchesController Class :
public class BatchesController {
Logger log = Logger.getLogger(BatchesController.class.getName());
public static BatchesController getInstance() {
if (batchesController == null) {
batchesController = new BatchesController(BatchDaoFactory.getDao());
}
return batchesController;
}
private static BatchesController batchesController = new BatchesController();
private final BatchDao batchDao;
public BatchesController(BatchDao BatchDao) {
this.batchDao = BatchDao;
}
// Do something
}
And below is the test that I have :
#RunWith(MockitoJUnitRunner.class)
public class GetAllBatchesTest {
#Mock
ExecutionContext context;
#Mock
HttpRequestMessage<String> request;
#Mock
BatchesController batchesController;
#Mock
BatchDao BatchDao;
#InjectMocks
GetAllBatches getAllBatchesMock = new GetAllBatches();
#Before
public void setUp() {
Map<String, String> map = new HashMap<>();
map.put("connector", "");
doReturn(Logger.getGlobal()).when(context).getLogger();
doReturn(map).when(request).getQueryParameters();
try (MockedStatic<BatchesController> utilities = Mockito.mockStatic(BatchesController.class)) {
utilities.when(BatchesController::getInstance).thenReturn(batchesController);
}
doAnswer((Answer<HttpResponseMessage.Builder>) invocationOnMock -> {
HttpStatus status = (HttpStatus) invocationOnMock.getArguments()[0];
return new HttpResponseMessageMock.HttpResponseMessageBuilderMock().status(status);
}).when(request).createResponseBuilder(any(HttpStatus.class));
}
#Test
public void testHttpTriggerJava() {
final HttpResponseMessage ret = getAllBatchesMock.run(request, context);
Assertions.assertEquals(ret.getStatus(), HttpStatus.OK);
}
When I run my test, it throws an error message :
java.lang.ExceptionInInitializerError
BatchesController.getInstance() is not actually returning the mock value.
I am not sure what is going wrong here ?
UPDATE :
I found out that the problem is because I am using Mockito-inline Mockito-inline fails to initiate mock on class but initiates mock only on interfaces

Answer 1

You are using a try-with-resources block to setup a static mock:
try (MockedStatic<BatchesController> utilities = Mockito.mockStatic(BatchesController.class)) {
utilities.when(BatchesController::getInstance).thenReturn(batchesController);
}
Remember that the static mock is only active in scope of the block - after you exit the block the resource is closed.
Thus, you need to:
move the static mock initialization from setup method to the test method
run code under test within the try-with-resources block