Loïc Faugeron has continued his series developing the code for a "Mars Lander" coding exercise with this latest post sharing the actual code for the event sourcing functionality started in the previous tutorial.

In this series we're building the software of a Mars Rover, according to the following specifications. It will allow us to practice the followings: Monolithic Repositories (MonoRepo), Command / Query Responsibility Segregation (CQRS), Event Sourcing (ES) and Test Driven Development (TDD). Up until now, we've implemented the first use case, "Landing a rover on Mars".

We've also created an event-sourcing package with the following interfaces: Event, AnEventHappened and EventStore. In this article, we're going to implement them.

He then starts in using phpspec to generate the Event class for him and gives it a basic structure. He fleshes this out with a bit of functionality (to make the tests pass) and moves on to the "AnEventHappened" class. He generates the class in the same way as before and adds a "just now" method to return the event that "just happened". The last class, the "EventStore" could do different things depending on the storage method, so he's delaying that for now and will implement it later.