No More SQLite - How to Write Tests With EF Core Using TestContainers - Daniel Ward

SQLite and in-memory providers can cause false positives/negatives in tests since they don’t exactly match production database behavior

TestContainers allows running tests against real database containers (like PostgreSQL) with minimal setup code

Key benefits of TestContainers:

• Uses same database engine as production
• Handles container lifecycle automatically
• Provides clean state between test runs
• Works with multiple database types and services
• Fast performance even with hundreds of tests

Respawn library helps efficiently reset database state between tests by creating foreign key dependency graphs

Collection fixtures in xUnit help optimize container reuse across test classes while maintaining isolation

Common integration test challenges addressed:

• Database state cleanup
• Schema management
• Port conflicts
• Container lifecycle management
• Test parallelization

TestContainers includes “Ryuk” resource reaper container to ensure cleanup even if tests crash

Setup requires minimal code:

• One line to create container
• One line to start it
• One line to dispose

Works well in CI/CD pipelines since it only requires Docker-compatible runtime

Knowledge is transferable since TestContainers exists for multiple languages and database types