Comparative Case Study Episode 1

London vs. Chicago, Episode 1

By Robert Martin & Sandro Mancuso

76 minJul 2018

And so it begins! London is first up. Sandro Mancuso takes the lead for the next five episodes, creating a Twitter-like app using the outside-in "London School" approach.

In this episode Sandro completes the first few use cases. The acceptance tests for those use cases pass. The unit tests and the production code are written.

And, in this episode, we see the first hint of the double edged sword of mocking: we see how the outside-in approach drives architecture. We see how the unit tests drive design. And we also see how the prodigious use of mocks may make the unit tests and production code fragile.

Note: You can find the code here. Three branches are of interest:

  1. The starting-point branch is where both implementations began.

  2. The openchat-outside-in branch captures the tomato by tomato history of the London approach.

  3. The openchat-unclebob branch captures the tomato by tomato history of the Chicago approach.