Slides for the Hexagonal Architecture kata at Softwerkskammer Berlin 2015-04

1. Hexagonal Architecture

2. Ports-And-Adapters / Hexagonal
Architecture
● Coined by Alistair Cockburn in 2005 !
● Referenced multiple times by:
– GooS
– Gerard Meszaros
– Uncle Bob
http://www.dossier-andreas.net/software_architecture/ports_and_adapters.htmlhttp://alistair.cockburn.us/Hexagonal+architecture

3. Some real world example

4. Test Double Adapter
Test fixture interface Port interface
implementation used by Behaviour tests

5. Consequences
● Highly testable as business rules can be tested without the
UI, Database, Web Server, or any other external element.
● It is easy to replace services by other ones that are more fit
in view of changing requirements
● Tests are guided by business scenarios - no waste
produced,
● „too high” granularity of test
● Emergent design
● Easy to refactor
● Test doubles must be in sync with real adapters contracts
(like in unit testing)

6. Test Pyramid

7. Links
● http://alistair.cockburn.us/Hexagonal+architect
ure
● http://blog.8thlight.com/uncle-bob/2012/08/13/t
he-clean-architecture.html
● http://culttt.com/2014/12/31/hexagonal-architec
ture/