Our team has decoupled multiple large legacy code bases without being slown down by structure-sensitive tests. In fact we were able to painlessly grow our suite of business critical tests while we were completely reimagining our internal structure and without our users being impacted.

We did this with a variation of the hexagonal architecture that we now call the beehive architecture. The beehive architecture defines the structure as well as decoupling and test patterns that help you scale beyond 10.000 lines of code. Its structure is that of multiple stacked hexagons that talk to each other only via their driving facades, which makes it look like a large beehive.

This talk explores the isolation mechanisms in the beehive that support decoupling even large applications and the refactoring-friendly test patterns that are possible due to the structure.