Mockito unit test cases for QueryResultCallBack() - one of the Query inner class

Dear Lalatendu,

This is a fully customized approach, and it's entirely up to you how you would like to write tests for it. You can draw inspiration from the code provided below:
 

public interface QueryResultsCallBack {
    void onCompletion(ResponseType responseType, QueryResult queryResult, Error error);
}

import org.junit.Test;
import org.mockito.Mockito;

public class QueryResultsCallBackTest {

    @Test
    public void testQueryResultsCallBack() {
        // Create a mock implementation of QueryResultsCallBack
        QueryResultsCallBack callBack = Mockito.mock(QueryResultsCallBack.class);

        // Define the expected arguments
        ResponseType responseType = /* create a mock ResponseType */;
        QueryResult queryResult = /* create a mock QueryResult */;
        Error error = /* create a mock Error */;

        // Simulate the onCompletion method call
        callBack.onCompletion(responseType, queryResult, error);

        // Verify that the onCompletion method was called with the expected arguments
        Mockito.verify(callBack).onCompletion(responseType, queryResult, error);
    }
}

A complete sample code:
 

import org.junit.Test;
import org.mockito.Mock;
import static org.mockito.Mockito.*;
import static org.junit.Assert.*;

public class YourClassTest {

    @Mock
    private Stack stack; // Mock the Stack dependency
    @Mock
    private Query query; // Mock the Query dependency
    @Mock
    private QueryResult queryResult; // Mock the QueryResult dependency
    @Mock
    private ResponseType responseType; // Mock the ResponseType dependency
    @Mock
    private Error error; // Mock the Error dependency (if needed)

    @Test
    public void testFetchQuery() {
        // Initialize the mocks and set up behavior
        when(stack.contentType(contentTypeUID)).thenReturn(stack); // Mock the chain calls
        when(stack.query()).thenReturn(query);

        // Simulate the behavior of the query.find() call
        doAnswer(invocation -> {
            QueryResultsCallBack callBack = invocation.getArgument(0);

            // Simulate a successful query result
            callBack.onCompletion(responseType, queryResult, error);

            // You can also set up queryResult.getResultObjects() to return a list if needed.

            return null;
        }).when(query).find(any(QueryResultsCallBack.class));

        // Call the method in your class that triggers the asynchronous code
        YourClass yourClass = new YourClass(stack); // Create an instance of YourClass with the mocked stack
        yourClass.fetchQuery();

        // Assert the expected behavior, e.g., check the state of listOfEntries
        // and other relevant variables
    }
}

Thank you !