Test-Driven Development with Mockito

Chapter 4. Understanding the Difference between Inside-out and Outside-in

In this chapter, we will cover different styles of TDD and write code using them.

Commonly, TDD has the following styles:

• Outside-in
• Inside-out

Understanding outside-in

Generally, the outside-in approach covers use case level functionality or is intended for acceptance tests. These tests provide regression suits and system documentation; if they fail, user/customer acceptance also fails.

In this category, developers pick a story or use case and drill into low-level unit tests. Basically, the objective is to obtain high-level design. The different system interfaces are identified and abstracted. Once different layers/interfaces are identified, unit-level coding can be started. ...