获得例外，参数不同：想要：

Question

@Spy
@InjectMocks
NotificationServiceImpl notificationService;

When i use like above, I am getting exception for a test as, Argument(s) are different: Wanted. But but while debugging control is going inside all methods and code coverage is happening.

@Mock
NotificationServiceImpl notificationService;

When i use like above, I am not getting any exception, but while debugging control is not going inside a few methods its impacting the code coverage. Could any one suggest me the proper mocking here. So that code coverage will happen as well as no exception will come. Stack Trace

Argument(s) are different! Wanted:
cwAlarmService.raiseNotificationProcessingAlarm(
    "device_id_value",
    <any string>
);
-> at com.cisco.inventory.service.NotificationMonitorTest.test_run_Exception_CW_Alarm(NotificationMonitorTest.java:189)
Actual invocations have different arguments:
cwAlarmService.raiseNotificationProcessingAlarm(
    "1b8722ad-0b9b-3327-98fb-5016fcf919f5",
    "Exception"
);
-> at com.cisco.inventory.scheduler.NotificationMonitor$TriggerNotificationDataCollection.run(NotificationMonitor.java:100)

    at com.cisco.inventory.service.NotificationMonitorTest.test_run_Exception_CW_Alarm(NotificationMonitorTest.java:189)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:59)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.springframework.test.context.junit4.statements.RunBeforeTestExecutionCallbacks.evaluate(RunBeforeTestExecutionCallbacks.java:74)
    at org.springframework.test.context.junit4.statements.RunAfterTestExecutionCallbacks.evaluate(RunAfterTestExecutionCallbacks.java:84)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
    at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
    at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
    at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:366)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:251)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97)
    at org.junit.runners.ParentRunner$4.run(ParentRunner.java:331)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:79)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:329)
    at org.junit.runners.ParentRunner.access$100(ParentRunner.java:66)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:293)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
    at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:413)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)
    at com.intellij.rt.junit.IdeaTestRunner$Repeater$1.execute(IdeaTestRunner.java:38)
    at com.intellij.rt.execution.junit.TestsRepeater.repeat(TestsRepeater.java:11)
    at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:35)
    at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:235)
    at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:54)

and this is the test

@Test
    public void test_run_Exception_CW_Alarm() throws IOException, InterruptedException {
        List<DeviceDetails> deviceDetailsList = new ArrayList<>();
        DeviceDetails deviceDetails = new DeviceDetails();
        deviceDetails.setDeviceId(ConstantsTest.DEVICE_ID_VALUE);
        deviceDetails.setCollectionStatus(Constants.COMPLETED);
        deviceDetails.setType("abc");
        deviceDetails.setIP("10.58");
        deviceDetailsList.add(deviceDetails);
        Mockito.when(inventoryDao.getAllDeviceDetails()).thenReturn(deviceDetailsList);
        Mockito.when(inventoryDao.getDeviceDetails(Mockito.any())).thenReturn(deviceDetails);
        NotificationData notificationData = getNotificationData();
        notificationData.setNotificationProcessingStatus(Constants.INIT);
        notificationData.setDeviceId("1b8722ad");
        Mockito.when(inventoryDao.getValidNotificationToBeProcessed(Mockito.any())).thenReturn(notificationData);
        notificationData.setNotificationProcessingStatus(Constants.PROCESSING);
        notificationData.setIsAlarm(Boolean.TRUE);

        List<StringPair> list = populateSVOModelPathStringPairs();
        StaticList.ModelPathMapData modelPathMapData = new StaticList.ModelPathMapData();
        modelPathMapData.setName(Constants.GET_QUERY_MAP_FOR_SVO);
        modelPathMapData.setModelPaths(list);
        StaticList staticList = new StaticList();
        staticList.setModelPathMap(modelPathMapData);
        Optional<StaticList> staticListOptional = Optional.of(staticList);

        Mockito.when(inventoryDao.findStaticListByID(Constants.SVO)).thenReturn(staticListOptional);
        Mockito.when(inventoryDao.saveNotificationProcessingStatus(Mockito.any(),Mockito.any())).thenReturn(notificationData);
        Mockito.doThrow(new RuntimeException("Exception")).when(notificationService).checkAndHandleDeleteNotifications(notificationData);

        notificationMonitor.run();

        Mockito.verify(cwAlarmService, Mockito.timeout(1000)).raiseNotificationProcessingAlarm(eq(ConstantsTest.DEVICE_ID_VALUE), Mockito.anyString());
    }

Answer 1

TL;DR

While mocking the methods of a spied object use doReturn(...).when(...) instead of when(...).thenReturn(...)

Longer explanation

Although in Mockito the mocks and spies looks similar, there are some important differences.

• @Mock stubs all the methods. The methods do nothing and return null by default.
• @Spy does not stub anything unless it is told to. It invokes the real methods of the spied object by default.

There is another important implementation difference:

• when(obj.someMethod(...)).thenReturn(value) - invokes the method someMethod and then stubs the method.
• doReturn(value).when(obj).someMethod(...) - does not invoke the method someMethod and stubs it right away.

These two approaches have similar effect while stubbing mocks. But in case of spies calling the real method of a real object can lead to unwanted side effects.

---

So when you are using @Spy with when(...).thenReturn(...) there are some hidden side effects, which in your particular case result in generating an actual UUID instead of returning the dummy value "device_id_value" .

This also explains why your unit test works properly while using @Mock .