Modern C++ Programming with Test-Driven Development

7.2 Tests Come FIRST

Wondering if you’ve built a good unit test? Vet it against the ​ FIRST​ mnemonic, devised by Brett Schuchert and Tim Ottinger. The mnemonic reminds you of a key part of TDD’s definition: tests come ​first​.

FIRST breaks down into the following:

• ​F​ for Fast

• ​I​ for Isolated

• ​R​ for Repeatable

• ​S​ for Self-verifying

• ​T​ for Timely

Fast

TDD supports incremental and iterative development through its core cycle of specify, build, and refactor. How long should a cycle take? The shorter, the better. You want to know as soon as your code either doesn’t work or breaks something else. The more code you grow between introducing a defect and discovering it, the more time you stand to waste in pinpointing and fixing the problem. You want ...