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How to write spring boot unit test for a method which calls another #Async method inside it?

I need to write integration test for "processEvent" method which calls a #Async method inside it. I tried writing a test for this method, but the issue was it did not save the Student object to the DB. However removing #Async annotation allows me to save the object. I want to know how should I write Test cases for this method, eliminating the #Async issue. I want to save the student object while testing. I have attached my code and below.
Here is the ClassA and it has the method I want to test.
#Service
public class ClassA {
private final ConfigurationProcessor<Student> configurationProcessor;
#Autowired
public ClassA(ConfigurationProcessor<Student> configurationProcessor) {
this.configurationProcessor = configurationProcessor;
}
public void processEvent(Configuration configuration) {
configurationProcessor.process(configuration);
}
}
This is the interface ConfigurationProcessor class
public interface ConfigurationProcessor<T> {
void process(Configuration configuration);
}
And this is its Impl class
#Service
public class ConfigurationProcessoeStudents10Impl implements ConfigurationProcessor<Student> {
private final StudentRepository studentRepository;
#Autowired
public ConfigurationProcessoeStudents10Impl(StudentRepository studentRepository) {
this.studentRepository = studentRepository;
}
#Override
#Async
public void process(Configuration configuration) {
studentRepository.save(Student.builder().Name(configuration.name).Age(configuration.age));
}
}
This is the Test I have written so far.
#EnableAutoConfiguration
#SpringBootTest
public class AudienceC10IT {
#Autowired
ClassA classA;
#Test
#Tag("VerifyProcess")
#DisplayName("Verify kafka event consumer from configuration manager")
void verifyProcess(){
Configuration configuration = new Configuration("lal",12);
classA.processEvent(configuration);
}
}

If you have have set up a ThreadPoolTaskExecutor bean you can Autowire it in your test.
Then, after you call your async method, you can await the termination.
Then you can check for the expected behaviour / result.
Something like this:
#Autowired
private ThreadPoolTaskExecutor asyncTaskExecutor;
#Test
void test() {
callAsyncMethod();
boolean terminated = asyncTaskExecutor.getThreadPoolExecutor().awaitTermination(1, TimeUnit.SECONDS);
assertAsyncBehaviour();
}

Why tested class based autowire annotation throw null exception?

I use Spring Boot 5 and JUnit in my project. I create a unit test to test the service.
Here is the service that I am testing:
#Service
#RequiredArgsConstructor
#Slf4j
public class BuilderServiceImpl implements BuilderService{
#Autowired
public AutoMapper autoMapper;
private final BuilderRepository builderRepository;
private final AdminUserRepository adminUserRepository;
#Override
public BuilderDto getByEmail(String email){
}
#Override
public List<BuilderMinDto> getAll() {}
#Override
public List<BuilderMinDto> getAll(int page, int size) {}
#Override
public SaveBuilderResponse create(Builder builder){
var str = autoMapper.getDummyText();
Builder savedBuilder = builderRepository.save(builder);
return new SaveBuilderResponse(savedBuilder);
}
}
And here is the test class that tests the service above:
#SpringBootTest
#RequiredArgsConstructor
#Slf4j
class BuilderServiceImplTest {
#Mock
private BuilderRepository builderRepository;
#Mock
private AdminUserRepository adminUserRepository;
private AutoCloseable autoCloseable;
private BuilderService underTest;
#BeforeEach
void setUp(){
autoCloseable = MockitoAnnotations.openMocks(this);
underTest = new BuilderServiceImpl(builderRepository,adminUserRepository);
}
#AfterEach
void tearDown () throws Exception{
autoCloseable.close();
}
#Test
void getByEmail(){}
#Test
#Disabled
void getAll() { }
#Test
#Disabled
void testGetAll() {}
#Test
void create() {
//given
Builder builder = new Builder();
builder.setName("John Johnson");
builder.setCompanyName("Builders Test");
builder.setEmail("test#builders.com");
//when
underTest.create(builder);
//then
ArgumentCaptor<Builder> builderArgumentCaptor = ArgumentCaptor.forClass(Builder.class);
verify(builderRepository)
.save(builderArgumentCaptor.capture());
Builder captureBuilder = builderArgumentCaptor.getValue();
assertThat(captureBuilder).isEqualTo(builder);
}
}
When I start to run the test class the create method in BuilderServiceImpl fired and on this row:
var str = autoMapper.getDummyText();
I get NullPointerException(autoMapper instance is null).
Here is the definition of AutoMapper class:
#Component
#Slf4j
#RequiredArgsConstructor
public class AutoMapper {
public String getDummyText(){
return "Hello From AutoMapper.";
}
}
As you can see I use #Component annotation to register the AutoMapper class to the IoC container and Autowired annotation to inject it into autoMapper property in BuilderServiceImpl class.
Why autoMapper instance is null? How can I make autoMapper to be initialized?

In order to make #Autowire work you have to use the instance of BuilderServiceImpl (object under test) created by spring itself.
When you create the object like this (by yourself, manually):
#BeforeEach
void setUp(){
....
underTest = new BuilderServiceImpl(builderRepository,adminUserRepository);
}
Spring doesn't know anything about this object, hence Autowiring won't work
Another thing that might be useful:
You've used #Mock for BuilderRepository and AdminUserRepository.
This are plain mockito annotation, and if you're using an integration/system test that runs the spring under the hood, probably this is not what you want:
Surely, it will create a mock, but it won't put it onto an application context, and won't substitute the beans of these classes that might have been created by spring.
So if this is what you want to achieve, you should use #MockBean instead.
This annotation belongs to Spring Testing framework rather than a plain mockito annotation.
All-in-all you might end up with something like this:
#SpringBootTest
class MyTest
{
#MockBean
BuilderRepository builderRepo;
#MockBean
AdminUserRepository adminUserRepo;
#Autowired // spring will inject your mock repository implementations
// automatically
BuilderServiceImpl underTest;
#Test
void mytest() {
...
}
}

Add #Autowire annotation Annotations on below fields. Error due your not initialized below object In BuilderServiceImpl
#Autowire
private final BuilderRepository builderRepository;
#Autowire
private final AdminUserRepository adminUserRepository;

Why are you creating BuildService manually? If you do this, set AutoMapper manualy too.
#BeforeEach
void setUp(){
autoCloseable = MockitoAnnotations.openMocks(this);
underTest = new BuilderServiceImpl(builderRepository,adminUserRepository);
underTest.setAutoMapper(new AutoMapper());
}
You are not using di.

Initialize Mocks in test before #BeforeStep

I have a custom reader with an #BeforeStep function in order to initialize some data. These data are comming from an external database.
#Component
public class CustomReader implements ItemReader<SomeDTO> {
private RestApiService restApiService;
private SomeDTO someDTO;
#BeforeStep
private void initialize() {
someDTO = restApiService.getData();
}
#Override
public SomeDTO read() {
...
return someDTO
}
}
In my unit test i need to mock the calls to the external database.
#RunWith(SpringRunner.class)
#SpringBootTest(classes = NedBatchApplication.class)
public class CustomReaderTest {
#Autowired
CustomReader customReader;
#Mock
RestApiService restApiService;
#Before
private void setup() {
MockitoAnnotations.initMocks(this);
ReflectionTestUtils.setField(customReader, "restApiService", restApiService);
Mockito.when(restApiService.getData().thenReturn(expectedData);
}
}
The problem i am facing is the #BeforeStep is executed before the #Before from the unit test, when i lauch my Test. So restApiService.getData() returns null instead of expectedData.
Is there a way to achieve what i want or do i need to do it with a different approach ?

After some reflexion with a co-worker he gave me a solution :
#RunWith(SpringRunner.class)
#SpringBootTest(classes = NedBatchApplication.class)
public class CustomReaderTest {
CustomReader customReader;
#Mock
RestApiService restApiService;
#Before
private void setup() {
MockitoAnnotations.initMocks(this);
Mockito.when(restApiService.getData().thenReturn(expectedData);
this.customReader = new CustomReader(restApiService);
}
#Test
public void test() {
customReader.initialize();
(...)
}
}

Are you certain that the BeforeStep is running before the Before annotation (by using logging or similar?).
It's possible your Mockito invocation is not fully correct. Try using Mockito.doReturn(expectedData).when(restApiService).getData() instead.
As an alternative approach, if the RestApiService was autowired in your custom reader, you'd be able to use the #InjectMocks annotation on the custom reader declaration in your test, which would cause the mocked version of your restApiService to be injected to the class during the test.

Usually when using Spring based tests, try to make dependencies like restApiService (the ones you would like to mock) to be spring beans, and then you can instruct spring to create mock and inject into application context during the application context creation with the help of #MockBean annotation:
import org.springframework.boot.test.mock.mockito.MockBean;
#RunWith(SpringRunner.class)
#SpringBootTest(classes = NedBatchApplication.class)
public class CustomReaderTest {
#MockBean
private RestApiService restApiService;
}

Excluding an ApplicationListener #Component in Spring Boot during tests

I am trying to have my test unit up and running, and I have encountered a weird issue. My application uses an ApplicationListener class annotated as a #Component to perform an operation during startup.
During tests I have mocked the service that contains the logic, but I found that even though Mockito's when instructions work well in controller scope, the bean is not initialized for this ApplicationListener class: instead of returning what I define in the test unit, it returns either false or null - depending on the data type returned by each method in the service.
Since I have not found any way to initialize the mocked service from the test unit for the ApplicationListener class, I have decided to exclude it. To do so I have tried different approaches, being the one most often used that of creating a test application context and change its configuration. Unfortunately, nothing I have seen is working - so I am here asking for help. If possible, I would prefer not touching the ApplicationListener class and do all related coding in the test code.
I am interested in any of the two possible solutions, if they can be done:
1.- Get the mocked behaviour during the ApplicationListener execution, but I have read somewhere that this cannot be done
2.- Exclude the #Component from the test unit somehow.
TestUnit.Java:
#RunWith(SpringRunner.class)
#SpringBootTest(classes = TestApplication.class, webEnvironment = WebEnvironment.RANDOM_PORT)
#AutoConfigureMockMvc
public class TestConfigurationService {
private MockMvc mockMvc;
#Autowired
private WebApplicationContext webApplicationContext;
#MockBean
private MockService mockService;
private void initMockBean () throws Exception {
when(mockService.isDoingSomething()).thenReturn(true);
}
#Before
public void setup() throws Exception {
// Spring mock context application setup
this.mockMvc = webAppContextSetup(webApplicationContext).build();
// Initialize ConsulService mock bean
initMockBean ();
}
}
TestApplication.java
#SpringBootApplication
#EnableAutoConfiguration
#ComponentScan(basePackages="my.base.package", excludeFilters = #Filter(type = FilterType.ASSIGNABLE_TYPE, classes = StartupConfiguration.class))
public class TestApplication {
public static void main(String[] args) {
SpringApplication.run(TestApplication.class, args);
}
}
Besides what is shown in the code, I have also tried this annotation in file TestApplication.java:
#SpringBootApplication(exclude={StartupConfiguration.class})
StartupConfiguration.java
#Component
public class StartupConfiguration implements ApplicationListener<ContextRefreshedEvent> {
#Autowired
private ConfigurationService configurationService;
#Override
public void onApplicationEvent(final ContextRefreshedEvent event) {
try {
configurationService.updateConfiguration();
} catch (Exception e) {
throw new RuntimeException ("Error", e);
}
}
}
ConfigurationService.java
public interface ConfigurationService {
public void updateConfiguration () throws Exception;
}
ConfigurationServiceImpl.java
#Service
#Transactional
public class ConfigurationServiceImpl implements ConfigurationService {
#Autowired
private MService mockService;
#Override
public void updateConfiguration() throws Exception {
if (mockService.isDoingSomething()==false)
throw new Exception ("Something went wrong");
}
}
Versions:
Spring Boot 1.5.4.RELEASE,
Java 1.8

You can create mock bean of the same type and mark it with #Primary annotation to replace real bean. You can achieve this by having test such configuration:
#Configuration
#Import(TestApplication.class)
public class TestConfiguration {
#Bean
#Primary
public ConfigurationService configurationService() {
return Mockito.mock(ConfigurationService.class);
}
}
then get this mock in test:
...
public class TestConfigurationService {
...
#Autowired
ConfigurationService configurationService;
#Before
public void setUp() {
when(mockService.isDoingSomething()).thenReturn(true);
}
}

Thanks, araxn1d. Your answer gave me the clue to solve this issue.
I mocked the StartupConfiguration class in TestUnit.java:
#MockBean
private StartupConfiguration startupConfiguration;
Though in this case I was lucky: application listeners don't have returning methods, so they don't need when test configuration. If I had required that some method there returned for example true or a value, this method would not apply.
But at least for application listeners, this is enough.

How to disable Spring autowiring in unit tests for #Configuration/#Bean usage

I want configure a component test using spring-test configuration inner class (#Configuration). Tested components has some services which I'd like to mock for the test. These services are classes (no interface used) and have spring annotations (#Autowired) in them. Mockito can easily mock them, however, I found no way of disabling spring autowiring.
Example how I can easily reproduce:
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration(classes = SomeTest.Beans.class)
public class SomeTest {
// configured in component-config.xml, using ThirdPartyService
#Autowired
private TestedBean entryPoint;
#Test
public void test() {
}
#Configuration
#ImportResource("/spring/component-config.xml")
static class Beans {
#Bean
ThirdPartyService createThirdPartyService() {
return mock(ThirdPartyService.class);
}
}
}
public class ThirdPartyService {
#Autowired
Foo bar;
}
public class TestedBean {
#Autowired
private ThirdPartyService service;
}
In this example "TestBean" represents the service to be mocked. I would NOT like "bar" to be injected by spring! #Bean(autowire = NO) does not help (in fact, that's the default value).
(Please save me from "use interfaces!" comments - the mocked service can be 3rd party which I can't do anything with.)
UPDATE
Springockito partially solves the problem, as long as you don't have to have anything else to configure (so you can't use configuration class with Springockito - it does not support it), but use mocks only.
Still looking for pure spring solution, if there's any...

Here is my solution to your problem:
import static org.mockito.Mockito.mockingDetails;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.InstantiationAwareBeanPostProcessorAdapter;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
#Configuration
public class MockitoSkipAutowireConfiguration {
#Bean MockBeanFactory mockBeanFactory() {
return new MockBeanFactory();
}
private static class MockBeanFactory extends InstantiationAwareBeanPostProcessorAdapter {
#Override
public boolean postProcessAfterInstantiation(Object bean, String beanName) throws BeansException {
return !mockingDetails(bean).isMock();
}
}
}
and then just
#Import(MockitoSkipAutowireConfiguration.class)
in your test #Configuration and you are all set

I solved it by creating FactoryBean for my bean instead of just mocking bean. At this way Spring don't try to autowire fields.
Factory bean helping class:
public class MockitoFactoryBean<T> implements FactoryBean<T> {
private final Class<T> clazz;
public MockitoFactoryBean(Class<T> clazz) {
this.clazz = clazz;
}
#Override public T getObject() throws Exception {
return mock(clazz);
}
#Override public Class<T> getObjectType() {
return clazz;
}
#Override public boolean isSingleton() {
return true;
}
}
Actual test context part:
#Configuration
public class TestContext {
#Bean
public FactoryBean<MockingService> mockingService() {
return new MockitoFactoryBean<>(MockingService.class);
}
}

Check Spring profiles. You don't need to disable auto wiring, you need to inject different beans for different configuration.

You could add the mocked service manually to the spring application context via org.springframework.beans.factory.config.SingletonBeanRegistry#registerSingleton. This way the mock is not post-processed by spring and spring does not attempt to autowire the mock. The mock itself will be injected into your tested bean.
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration(classes = SomeTest.Beans.class)
public class SomeTest {
// configured in component-config.xml, using ThirdPartyService
#Autowired
private TestedBean entryPoint;
#Autowired
private ThirdPartyService thirdPartyServiceMock;
#Test
public void test() {
}
#Configuration
static class Beans {
#Autowired
private GenericApplicationContext ctx;
#Bean
TestedBean testedBean() {
ctx.getBeanFactory().registerSingleton("thirdPartyService", mock(ThirdPartyService.class));
return new TestedBean();
}
}
public static class ThirdPartyService {
#Autowired
Object bar;
}
public static class TestedBean {
#Autowired
private ThirdPartyService service;
}
}

I am in quite the same situation.
What I found that if you do not set the context loader by #ContextConfiguration annotation on your test class, the default context loader will be used, which derived from AbstractGenericContextLoader. I had a look at its source and turned out it registers all the bean post processors which are responsible for reading annotations such #Autowired. In other words, annotation config is enabled by default.
So the main problem is that there are two configurations which are in conflict: in the java config we said that autowiring is not needed, while the autowired annotation tells the opposite. The real question is how to disable the annotation processing in order to eliminate the undesired configuration.
As far as I know there is no such spring implementation of ContextLoader which would not be derived from AbstractGenericContextLoader so I guess the only we can do is to write our own. It would be something like this:
public static class SimpleContextLoader implements ContextLoader {
#Override
public String[] processLocations(Class<?> type, String... locations) {
return strings;
}
#Override
public ApplicationContext loadContext(String... locations) throws Exception {
// in case of xml configuration
return new ClassPathXmlApplicationContext(strings);
// in case of java configuration (but its name is quite misleading)
// return new AnnotationConfigApplicationContext(TestConfig.class);
}
}
Of course it would be worth to spend more time to find out how to implement ContextLoader properly.
Cheers,
Robert

There are so many ways of doing this, I'm pretty sure that this answer will be incomplete, but here are a few options...
As currently seems to be recommended practice, use constructor injection for your services rather than autowiring the fields directly. This makes testing like this so much easier.
public class SomeTest {
#Mock
private ThirdPartyService mockedBean;
#Before
public void init() {
initMocks(this);
}
#Test
public void test() {
BeanUnderTest bean = new BeanUnderTest(mockedBean);
// ...
}
}
public class BeanUnderTest{
private ThirdPartyService service;
#Autowired
public BeanUnderTest(ThirdPartyService ThirdPartyService) {
this.thirdPartyService = thirdPartyService;
}
}
By doing that, you can also mix up autowired and mocked services by autowiring into the test itself and then constructing the beans under test with the most useful mix of autowired and mocked beans.
A reasonable alternative is to use Spring profiles to define stub services. This is particularly useful when wish to use the same stubbed features in multiple tests:
#Service
#Primary
#Profile("test")
public class MyServiceStub implements MyService {
// ...
}
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration(classes = SomeTest.Beans.class)
#ActiveProfiles({"test"})
public class SomeTest {
// ...
}
By using the #Primary annotation, it ensures that this stub bean will be used instead of any other bean implementing the MyService interface. I tend to use this approach for things like email services, where by changing profile, I'm able to switch between a real mail server and Wiser.