How to mock a util class with static methods in Junit5 using wcm io?

Question

Hi,
I am writing my first junit test for a workflow process and I am trying to write it using the AEM context (WCM io) and my workflow process also has a util class method used in it. Here I am facing two problems one with providing the context (which contains the resource resolver factory and the other objects) to the workflow process execute method in the test method and the mocking of utils class in Test class.
 
Note: We can mock the util class if we use powermockito, but powermockito works only with Junit4, but I have to write my test case in Junit5.
 
below is an excerpt of my code:
@ExtendWith(AemContextExtension.class)@ExtendWith(MockitoExtension.class)@MockitoSettings(strictness = Strictness.LENIENT)public class WorkflowProcessTest {
AemContext context = new AemContext(ResourceResolverType.RESOURCERESOLVER_MOCK);@MockWorkItem workItem;@MockWorkflowData workflowData;@MockWorkflowSession workflowSession;@MockMetaDataMap metaDataMap;@Mockprivate QueryBuilder queryBuilder;@Mockprivate Query qbQuery;@MockResourceResolverFactory resourceResolverFactory;
@Mockprivate SearchResult qbResult;@MockSession adminSession;@MockResourceResolver resolver;
WorkflowProcess workflowProcess;
@BeforeEachvoid setUp() throws LoginException {resourceResolverFactory = context.registerService(ResourceResolverFactory.class, new MockResourceResolverFactory());context.registerAdapter(ResourceResolver.class, Session.class, mock(Session.class));mockPayload();resolver = context.resourceResolver();when(resourceResolverFactory.getServiceResourceResolver(any())).thenReturn(resolver);
}
@2785667void testExecute() throws RepositoryException,WorkflowException {
//Some more code hereworkflowProcess = new WorkflowProcess();workflowProcess.execute(workItem, workflowSession, metaDataMap);//workflowProcess = context.registerInjectActivateService(new workflowProcess());verifyMetadata(metadataNode);
}
private void verifyMetadata(Node metadataNode) throws RepositoryException {//assert statement here
}
void mockPayload() {//payload mock here
}}
 
Can someone help on those two?
 
Your help is much appreciated.
 
Thanks in advance,Adilakshmi

BrianKasingli · Accepted Answer

I've actually written a blog for this for JUNIT5, with code examples and dependencies:

PowerMock is a Java framework that allows you to unit test code that uses static methods, constructors, and private methods. PowerMock uses a combination of bytecode manipulation and reflection to enable the mocking of these types of methods.

PowerMock is not officially supported by JUnit 5. PowerMock is built on top of EasyMock and provides additional functionality such as the ability to mock static methods, constructors, and private methods. PowerMock uses a different test runner than the one provided by JUnit 5, so it is not directly compatible with JUnit 5.

Alternatively, you can use mockito-inline for inline mocking, it allows you to mock static methods, final classes, and methods, and more.

JUnit 5 provides its own extension model that allows for the creation of custom test runners and the registration of extensions. You could write your own test runner for PowerMock that works with JUnit 5 or use a different mocking framework that is compatible with JUnit 5.

Utils Class:

public class Utils {
    public static String getString() {
        return "Original string";
    }
}

Test Class:

import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertEquals;
import org.mockito.Mockito;

public class MyTest {

    @2785667
    public void testStaticMethod() {
        // mock the static method of the Utils class
        Mockito.mockStatic(Utils.class);
        Mockito.when(Utils.getString()).thenReturn("Mocked string");
       
        // create an instance of the class that calls the static method
        MyClass myClass = new MyClass();
        assertEquals("Mocked string", myClass.getStringFromUtils());
    }
}

Read more:Mocking Static Methods in JUNIT5 - Sourced Code

ArpitVarshney · Answer

Hi @adilakshmi

WCM io library is a utility to mock AEM resources during test time. If you have created a new static method then please avoid using creating a static method as this won't be considered as best practice in java and for the same reason mockito framework doesn't provide the capability to mock static methods by default. You can create services and methods to achieve the same.
However for mocking the static method, please refer below points:

Approach 1: If You doesn't want to use any additional dependency then treat this method as a private method and mock it line by line.
Approach 2: Use power mock API, there is a lot of documentation available online. You can refer https://dzone.com/articles/using-powermock-mock-static
Approach 3:Use mockito inline. You can refer to this https://howtodoinjava.com/mockito/mock-static-methods/

Regards,

Arpit Varshney

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