Obey the Testing Goat!

Folks I've written a new book!

Along with my coauthor Bob, we are proud to release "Architecture Patterns with Python", which you can find out more about at cosmicpython.com.

The cosmic soubriquet is a little joke, Cosmos being the opposite of Chaos in ancient Greek, so we want to propose patterns to minimise chaos in your applications.

But the subtitle of the book is Enabling TDD, DDD, and Event-Driven Microservices, and the TDD part is relevant to this blog, and fans of the Testing Goat. In my two years at MADE and working with Bob, I've refined some of my thinking and some of the ways I approach testing, and I think if I were writing TTDwP again today, I might change the way I present some things.

In brief:

• Mocking is not the only way to handle external (I/O et al) dependencies for your unit tests. Other techniques are possible, and often offer major benefits

• If you really want to get to a test pyramid (where unit tests outnumber slow/e2e/integration tests by an order of magnitude), then you'll probably need to make some specific design choices around identifying business logic and decoupling it from infrastructure code.

• When deciding what kind of unit tests to write, there's a lot to be said for writing them at the highest level of abstraction possible. It gives you more room to refactor later.

If you're curious about those questions, head on over to cosmicpython.com, and let me know what you think!