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Retryable annotation - Junit5 - Mockito - is it possible

Is it possible to write unit test using Junit 5 mockito for retryable annotations?
I am having a service interface which has only one method, which downloads the file from remote url
#service
interface downloadpdf{
#Retryable(value = { FileNotFoundException.class, HttpClientErrorException.class }, maxAttempts = 5, backoff = #Backoff(delay = 1000))
public string downloadpdffile(string remoteurl, string pdfname);
}
I have tried referring sites and found using Spring4JunitRunner implementation to test retry. Got confused with implementation. Is it possible to write unit test using Junit 5 mockito for retryable annotations?. Could you please elaborate on the solution here?

You need to use #SpringJUnitConfig (which is the equivalent of the JUnit4 runner). Or #SpringBootTest as you are using Boot.
#Retryable only works with beans managed by Spring - it wraps the bean in a proxy.
#SpringBootApplication
#EnableRetry
public class So71849077Application {
public static void main(String[] args) {
SpringApplication.run(So71849077Application.class, args);
}
}
#Component
class RetryableClass {
private SomeService service;
void setService(SomeService service) {
this.service = service;
}
#Retryable
void retryableMethod(String in) {
service.callme();
throw new RuntimeException();
}
#Recover
void recover(Exception ex, String in) {
service.failed();
}
}
interface SomeService {
void callme();
void failed();
}
#SpringBootTest
class So71849077ApplicationTests {
#MockBean
SomeService service;
#Test
void testRetry(#Autowired RetryableClass retryable) {
SomeService service = mock(SomeService.class);
retryable.setService(service);
retryable.retryableMethod("foo");
verify(service, times(3)).callme();
verify(service).failed();
}
}

I was also trying to implement this using Junit5.
Tried various options but that didn't help. Then after googling for few hours, got the following link and it helped to succeed.
https://doctorjw.wordpress.com/2022/04/29/spring-testing-a-single-bean-in-junit-5-springextension/
Reference code below, for detailed explanation, please refer the blog.
#Component
public class MyClass {
private ObjectMapper objectMapper;
private RestTemplate restTemplate;
#Value("${testValue:5}")
private int value;
#Retryable(....)
public void doStuff() throws SomeException {
...
}
}
What I’ve discovered is, if I declare my test class this way:
#ExtendWith( SpringExtension.class )
#Import( { MyClass.class, ObjectMapper.class } )
#EnableRetry
public class MyClassTest {
#Autowired
private MyClass myClass;
#MockBean
private RestTemplate restTemplate;
#Autowired
private ObjectMapper objectMapper;
#BeforeEach
public void setup() {
// If we are going to jack with the object configuration,
// we need to do so on the actual object, not the Spring proxy.
// So, use AopTestUtils to get around the proxy to the actual obj.
TestingUtils.setFieldValue( AopTestUtils.getTargetObject( myClass ), "value", 10 );
}
}
You will notice the inclusion of 1 other class, TestingUtils.class. This class looks like:
public class TestingUtils {
public static void setFieldValue( Object object, String fieldName, Object value ) {
Field field = ReflectionUtils.findField( object.getClass(), fieldName );
ReflectionUtils.makeAccessible( field );
ReflectionUtils.setField( field, object, value );
}
}
All credits goes to the author of the blog.

First mock of the method applied always

I want to test a few cases in a method by mocking external dependency to return different results for every test case. But when always returns what is defined at first time (in this example - empty set) and that brokes the next tests.
If I run tests one by one they pass successfully but when I run the whole class only the first test pass and others fail.
Testing class:
class ExampleTest {
#Mock
private Dao dao;
#Mock
private Validator validator;
#Spy
#InjectMocks
Controller controller;
#BeforeEach
void setUp() {
initMocks(this);
}
private final static Set DATA = Set.of("data1", "data2");
#Test
void firstTest() throws UserDashboardException, DashboardException, WidgetException {
when(validator.filter(DATA)).thenReturn(Collections.emptySet());
assertThrows(Exception.class, () -> controller.create(DATA));
}
#Test
void secondTest() throws UserDashboardException, DashboardException, WidgetException {
when(validator.filter(DATA)).thenReturn(DATA);
controller.create(DATA);
verify(dao, times(1)).create(eq(DATA));
}
}
Tested class:
public class Controller {
private Dao dao;
private Validator validator;
public Controller(Dao dao,Validator validator) {
this.dao = dao;
this.validator = validator;
}
public String create(Set<String> data) {
data = validator.filter(data);
if (data.isEmpty()) {
throw new Exception("Invalid data.");
}
return dao.create(data);
}
}
So, in both tests create method throws an exception which is not what I expect. Maybe I miss some point?

Have you tried with doReturn method?
doReturn(DATA).when(validator).filter(DATA)
which can be import from org.mockito.Mockito.doReturn;
Edited: there might be a bug inside your code implementation:
data = validator.filter(data);

Spring bean scope for "one object per test method"

I have a test utility for with I need to have a fresh instance per test method (to prevent that state leaks between tests). So far, I was using the scope "prototype", but now I want to be able to wire the utility into another test utility, and the wired instances shall be the same per test.
This appears to be a standard problem, so I was wondering if there is a "test method" scope or something similar?
This is the structure of the test class and test utilities:
#RunWith(SpringRunner.class)
#SpringBootTest
public class MyTest {
#Autowired
private TestDriver driver;
#Autowired
private TestStateProvider state;
// ... state
// ... methods
}
#Component
#Scope("prototype") // not right because MyTest and TestStateProvider get separate instances
public class TestDriver {
// ...
}
#Component
public class TestStateProvider {
#Autowired
private TestDriver driver;
// ...
}
I'm aware that I could use #Scope("singleton") and #DirtiesContext(classMode = ClassMode.AFTER_EACH_TEST_METHOD) but this refreshes more than I need – a new TestDriver instance for each test would be enough. Also, this approach is error-prone because all tests using the TestDriver would need to know that they also need the #DirtiesContext annotation. So I'm looking for a better solution.

It is actually pretty easy to implement a testMethod scope:
public class TestMethodScope implements Scope {
public static final String NAME = "testMethod";
private Map<String, Object> scopedObjects = new HashMap<>();
private Map<String, Runnable> destructionCallbacks = new HashMap<>();
#Override
public Object get(String name, ObjectFactory<?> objectFactory) {
if (!scopedObjects.containsKey(name)) {
scopedObjects.put(name, objectFactory.getObject());
}
return scopedObjects.get(name);
}
#Override
public void registerDestructionCallback(String name, Runnable callback) {
destructionCallbacks.put(name, callback);
}
#Override
public Object remove(String name) {
throw new UnsupportedOperationException();
}
#Override
public String getConversationId() {
return null;
}
#Override
public Object resolveContextualObject(String key) {
return null;
}
public static class TestExecutionListener implements org.springframework.test.context.TestExecutionListener {
#Override
public void afterTestMethod(TestContext testContext) throws Exception {
ConfigurableApplicationContext applicationContext = (ConfigurableApplicationContext) testContext
.getApplicationContext();
TestMethodScope scope = (TestMethodScope) applicationContext.getBeanFactory().getRegisteredScope(NAME);
scope.destructionCallbacks.values().forEach(callback -> callback.run());
scope.destructionCallbacks.clear();
scope.scopedObjects.clear();
}
}
#Component
public static class ScopeRegistration implements BeanFactoryPostProcessor {
#Override
public void postProcessBeanFactory(ConfigurableListableBeanFactory factory) throws BeansException {
factory.registerScope(NAME, new TestMethodScope());
}
}
}
Just register the test execution listener, and there will be one instance per test of all #Scope("testMethod") annotated types:
#RunWith(SpringRunner.class)
#SpringBootTest
#TestExecutionListeners(listeners = TestMethodScope.TestExecutionListener.class,
mergeMode = MergeMode.MERGE_WITH_DEFAULTS)
public class MyTest {
#Autowired
// ... types annotated with #Scope("testMethod")
}

I ran into the same problem some time ago and came to this solution:
Use Mocks
I wrote some methods to create specific mockito settings to add behavior to each mock.
So create a TestConfiguration class with following methods and bean definition.
private MockSettings createResetAfterMockSettings() {
return MockReset.withSettings(MockReset.AFTER);
}
private <T> T mockClass(Class<T> classToMock) {
return mock(classToMock, createResetAfterMockSettings());
}
and your bean definition will look like:
#Bean
public TestDriver testDriver() {
return mockClass(TestDriver .class);
}
MockReset.AFTER is used to reset the mock after the test method is run.
And finally add a TestExecutionListeners to your Test class:
#TestExecutionListeners({ResetMocksTestExecutionListener.class})

How to invoke #BeforeMethod block before #PostConstruct

I am writing below Spring Unit test code. Unit test #Before method is not getting executed. Since it is directly running #PostConstruct i am getting erorrs Caused by: java.lang.IllegalArgumentException: rate must be positive because the default value is 0.00. I want to set some value to request max limit so that postcontstruct block will go through smoothly. what is wrong in my code? Please help.
#Component
public class SurveyPublisher {
#Autowired
private SurveyProperties surveyProperties;
#PostConstruct
public void init() {
rateLimiter = RateLimiter.create(psurveyProperties.getRequestMaxLimit());
}
}
public void publish() {
rateLimiter.acquire();
// do something
}
}
//Unit test class
public class SurveyPublisherTest extends AbstractTestNGSpringContextTests {
#Mock
SurveyProperties surveyProperties;
#BeforeMethod
public void init() {
Mockito.when(surveyProperties.getRequestMaxLimit()).thenReturn(40.00);
}
#Test
public void testPublish_noResponse() {
//do some test
}
}

Just realized it will always run postConstruct method before Junit callback methods cause spring takes the precedence. As explained in the documentation -
if a method within a test class is annotated with #PostConstruct, that
method runs before any before methods of the underlying test framework
(for example, methods annotated with JUnit Jupiter’s #BeforeEach), and
that applies for every test method in the test class.
Solution to you issue -
As #chrylis commented above refactor your SurveyPublisher to use constructor injection to inject the rate limiter. So you can then easily test.
Inject Mock/Spy bean which is causing the problem
Create test config to give you the instance of the class to use as #ContextConfiguration
#Configuration
public class YourTestConfig {
#Bean
FactoryBean getSurveyPublisher() {
return new AbstractFactoryBean() {
#Override
public Class getObjectType() {
return SurveyPublisher.class;
}
#Override
protected SurveyPublisher createInstance() {
return mock(SurveyPublisher.class);
}
};
}
}

Here is the simple one worked.
#Configuration
#EnableConfigurationProperties(SurveyProperties.class)
static class Config {
}
#ContextConfiguration(classes = {
SurveyPublisherTest.Config.class })
#TestPropertySource(properties = { "com.test.survey.request-max-limit=1.00" })
public class SurveyPublisherTest extends AbstractTestNGSpringContextTests {
//Remove this mock
//#Mock
//SurveyProperties surveyProperties;
}

Using #InjectMocks to replace #Autowired field with a mocked implementation

I want to replace an autowired class of a service in my spring boot app with a mocked implementation of that class that I created specifically for testing.
I chose to create this mocked implementation because the behaviour of this class is too complicated to mock using mockito as it requires multiple other mocks itself.
I am not able to work out how to inject this mocked implementation into the service.
Here is a minimal example of the situation:
#Service
public class ServiceIWantToTestImpl implements ServiceIWantToTest{
#Autowired
ComplicatedDependency complicatedDependency;
#Override
public void methodUsingDependency(){
String string = complicatedDependency.doSomething();
System.out.println(string);
}
}
public class MockComplicatedDependency implements ComplicatedDepencency{
public MockComplicatedDependency(...){
// Inject other mocked objects into this mock
}
public String doSomthing(){
// This would be a mocked version of this function for testing
return "test";
}
}
#RunWith(MockitoJUnitRunner.class)
public class TestingTheService(){
#InjectMock
private static ServiceIWantToTest serviceIWantToTest = new ServiceIWantToTestImpl();
#Mock
ComplicatedDependency mockComplicatedDependency;
#BeforeClass
public static void init(){
mockComplicatedDependency = new MockComplicatedDependency(...);
}
#Test
public void testAttempt(){
serviceIWantToTest.methodUsingDependency(); // This method calls complicatedDependency.doSomething() which does not run the mocked version in MockComplicatedDependency which I wanted to inject, and would always return null instead of the "test" string I put in this example.
}
}

Do you have to use Mockito annotations to setup dependencies for the class under test?
If that is not the main constraint why not just do the plain simple setup and introduce a constructor or a setter in ServiceIWantToTestImpl class for the ComplicatedDependency field and set the dependency in your test setup directly to whatever impl of ComplicatedDependency you like e.g.:
#Service
public class ServiceIWantToTestImpl implements ServiceIWantToTest {
#Autowired
ComplicatedDependency complicatedDependency;
public ServiceIWantToTestImpl() {
}
public ServiceIWantToTestImpl(ComplicatedDependency complicatedDependency) {
this.complicatedDependency = complicatedDependency;
}
#Override
public void methodUsingDependency(){
String string = complicatedDependency.doSomething();
System.out.println(string);
}
}
public class TestingTheService {
private static ServiceIWantToTestImpl serviceIWantToTest;
#BeforeClass
public static void init(){
serviceIWantToTest = new ServiceIWantToTestImpl(new MockComplicatedDependency());
}
#Test
public void testAttempt() {
serviceIWantToTest.methodUsingDependency();
}
}
That is one way.
To make it work with Mockito, You could to use #Spy instead of #Mock like this:
#RunWith(MockitoJUnitRunner.class)
public class TestingTheService {
#InjectMocks
private static ServiceIWantToTestImpl serviceIWantToTest = new ServiceIWantToTestImpl();
#Spy
private static ComplicatedDependency complicatedDependency = new MockComplicatedDependency();
#BeforeClass
public static void init() {
}
#Test
public void testAttempt() {
serviceIWantToTest.methodUsingDependency();
}
}
Though this is a bit of a hack. I strongly recommend that you read the JavaDoc of the #Spy annotation and make sure it's expected use is what you really need for your test.