Adding tests first
In this section, we will review the trade-offs of adding a test first before writing the production code to make it pass.
Previous chapters have followed a test-first approach to writing code. We write a test before writing production code to make that test pass. This is a recommended approach, but it is important to understand some of the difficulties associated with it as well as considering its benefits.
Test-first is a design tool
The most important benefit of writing tests first is that a test acts as a design aid. As we decide what to write in our test, we are designing the interface to our code. Each of the test stages helps us consider an aspect of software design, as illustrated by the following diagram:
Figure 12.1 – Test-first aids design
The Arrange step helps us think about how the code under test relates to the bigger picture of the whole code base. This step helps us design how the code will fit into the...
