Testing Strategies for Hexagonal Architecture

Hexagonal architecture is considered particularly testable. In practice, however, it often remains unclear which tests you should actually write: Unit tests for each class, integration tests against the real database, or E2E tests through the UI? This presentation shows a test strategy derived directly from the architecture itself. Starting with Khorikov's four quality characteristics for tests, we will look at the test types of Hexagonal Architecture: Port-to-Port tests for business logic, Adapter tests with Testcontainers for the boundaries, and System Integration tests for the interaction. We will also address the questions that determine in everyday practice whether a test strategy holds up: Where do test data come from? When is a fake better than a mock? How do architecture tests secure the dependency rules of the hexagon? And why does Line Coverage say so little about how good the tests actually are? Finally, we go beyond the boundaries of a single hexagon: How do you test multiple services together without running into fragile E2E tests? Contract tests provide an answer to this. Speaker: Andreas Jürgensen is a software architect with several years of experience as a software developer. His particular focus is on the modernization of legacy systems as well as automated testing and Collaborative Modeling - areas he considers essential components of sustainable and maintainable software development. He is the founder and CEO of FOURTEEN IT, where he supports companies and development teams as a coach and consultant through training and consulting in the design and implementation of modern software systems.