TDD in Legacy Code - ATDD for User Stories - External System DSL

How do we apply ATDD when the External System DSL isn't implemented yet? We'll then need to implement the External System DSL & Driver, before we can implement the System.

🔒Hello, this is Valentina with a premium issue of the Optivem Journal. I help Engineering Leaders & Senior Software Developers apply TDD in Legacy Code. This article is part of the TDD in Legacy Code series. To get these articles in your inbox every week, subscribe:

---

How to handle implementing External System DSL?

Previously, we covered the core process of applying ATDD for User Stories. However, in that core process, we assumed that the DSL already exists.

However, what happens when the External System DSL doesn’t exist? We need to implement the External System DSL and the External System Driver before going towards System implementation.

Here are the steps to introduce ATDD for new User Stories in Legacy Code, in the case where the External System DSL does not exist. I’ll provide you with step-by-step guidance on how to introduce ATDD in your GitHub Sandbox Project. I’ll review & provide feedback in the comments: ⬇️⬇️⬇️