How do you test your hexagonal architecture applications?

2 Why use Hexagonal Architecture?

One of the main benefits of using Hexagonal Architecture is that it enables testing the core logic of the application independently from the external dependencies. This means that you can use unit tests or integration tests to verify the behavior and functionality of the inside layer, without relying on the availability or performance of the outside layer. You can also use mock objects or stubs to simulate the outside layer, or swap different adapters for different environments or scenarios. Another benefit of using Hexagonal Architecture is that it allows for easier maintenance and evolution of the application, by reducing the coupling and complexity of the code. You can change or replace the outside layer without affecting the inside layer, or vice versa, as long as you respect the contracts defined by the ports and adapters.

3 How to use Hexagonal Architecture?

There is no one-size-fits-all way to use Hexagonal Architecture, as it depends on the context and requirements of each application. However, some general guidelines and best practices can help you design and implement it effectively. For example, you should identify and separate the core domain logic from the external dependencies, and define clear and consistent interfaces for the ports and adapters. You should also follow the dependency inversion principle, which states that the inside layer should depend on abstractions (ports), not on concretions (adapters). You should also apply the principle of least knowledge, which states that the inside layer should only communicate with the ports that it needs, not with the adapters directly. Finally, you should use dependency injection, which is a technique that allows you to inject the adapters into the ports at runtime, rather than hard-coding them.

5 What are some books and tutorials on Hexagonal Architecture?

If you're interested in learning more about Hexagonal Architecture, there are several resources available. For example, Tom Hombergs' book Get Your Hands Dirty on Clean Architecture provides an introduction to the basics and benefits of Hexagonal Architecture and how to implement it in a web application. Vaughn Vernon's Implementing Domain-Driven Design explains how to use Domain-Driven Design in conjunction with Hexagonal Architecture. Additionally, Cosmin Stejerean's Hexagonal Architecture in Python tutorial shows how to use Hexagonal Architecture with a Python application and REST API, while Carlos Mendible's Hexagonal Architecture with .NET Core offers guidance on using Hexagonal Architecture with .NET Core and Azure Functions.