Part 3 is where we apply all the techniques we have learned to complete our application. Wordz is a web service that plays a word guessing game. We build on the core domain logic we have already built, adding storage via a Postgres database accessed using SQL and providing web access by implementing an HTTP REST API.

We will use integration tests to test-drive our database and API implementations, making use of test frameworks that simplify these tasks. In the final chapter of the book, we will bring everything together to confidently run our test-driven Wordz application.

This part has the following chapters:

• Chapter 13, Driving the Domain Layer
• Chapter 14, Driving the Database Layer
• Chapter 15, Driving the Web Layer