advanced~5h
Testcontainers Deep Dive
Why an in-memory H2 database can let a broken query pass every test and still break in production, how Testcontainers spins up real, disposable Docker containers for integration tests, the lifecycle and reuse patterns that keep a container-backed suite fast, and a full worked example testing a Spring Data JPA repository against a real containerized PostgreSQL instance.
Learning objectives
- Explain the H2-versus-real-database dialect mismatch problem and why it matters for native queries and migrations
- Set up a Testcontainers-backed integration test using @Container and @DynamicPropertySource
- Describe the container lifecycle and the singleton container reuse pattern for fast test suites
- Write a @DataJpaTest-style repository test that runs against a real containerized PostgreSQL instance
- Identify when Testcontainers is worth its setup cost versus when an in-memory database is sufficient
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Testcontainers Deep Dive