Java:
টেস্ট লিখা

<dependency>
    <groupId>org.junit.jupiter</groupId>
    <artifactId>junit-jupiter</artifactId>
    <version>5.9.0</version>
    <scope>test</scope>
</dependency>

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

public class CalculatorTest {
    
    @Test
    public void testAdd() {
        Calculator calculator = new Calculator();
        assertEquals(5, calculator.add(2, 3), "2 + 3 এর মান 5 হওয়া উচিত");
    }
}

<dependency>
    <groupId>org.mockito</groupId>
    <artifactId>mockito-core</artifactId>
    <version>4.5.1</version>
    <scope>test</scope>
</dependency>

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

public class UserServiceTest {

    @Test
    public void testGetUsername() {
        // Create a mock UserRepository
        UserRepository mockRepository = mock(UserRepository.class);

        // Mock অবজেক্টের আচরণ নির্ধারণ
        when(mockRepository.getUsername(1)).thenReturn("john_doe");

        UserService userService = new UserService(mockRepository);
        
        assertEquals("john_doe", userService.getUsername(1), "User ID 1 এর জন্য john_doe থাকা উচিত");
    }
}