lab-3

Lab 3: Sliced Testing - Persistence Layer & Testcontainers

Learning Objectives

• Learn how to test JPA repositories with @DataJpaTest
• Understand the differences between in-memory databases and real databases for testing
• Get started with Testcontainers for PostgreSQL
• Understand transaction management, flushing, and cleanup in tests
• Practice using @ServiceConnection for Testcontainers integration

Hints

• @DataJpaTest focuses on JPA repositories and configures an in-memory database by default
• Use @Testcontainers and @Container for PostgreSQL-based tests
• Spring Boot's @ServiceConnection simplifies Testcontainers configuration
• Flyway migrations run automatically with spring.jpa.hibernate.ddl-auto=validate
• Be mindful of transaction boundaries in your tests

Exercises

Exercise 1: Testing Repositories with @DataJpaTest

This exercise focuses on testing the BookRepository with JPA-specific test configuration.

Tasks:

1. Open Exercise1DataJpaTest.java in the exercises package
2. Implement tests for the repository methods
3. Test both standard CRUD operations and custom queries
4. Consider using Testcontainers for PostgreSQL-specific features

Tips:

• @DataJpaTest automatically configures an in-memory database
• For PostgreSQL-specific tests, use Testcontainers with @ServiceConnection
• Test both positive and negative scenarios
• Be aware of the searchBooksByTitleWithRanking native query that requires PostgreSQL
• The solution is available in Solution1DataJpaTest.java