Test Your Legacy Code

Everybody wants to do test-driven development, but switching to TDD or BDD on an existing project that doesn’t have tests presents special challenges. Often, the current code is a tangled mess of dependencies that defeats the very concept of unit testing. Worse, if somebody has attempted TDD in the past, you might have a test suite that needs to be fixed before any new tests can be written.

Don’t give up. Adding test-coverage and TDD to your application will make it easier.

This session will describe techniques that you can use to bootstrap a test-driven process into your project. You’ll see how to use “black-box” techniques that don’t depend on the structure of the code and “white-box” techniques that interact with the code more directly.

Topics covered will include:

• Using Cucumber to perform black-box testing.
• Using RSpec to perform white-box testing.
• Using mocks to isolate legacy code.
• Safer refactoring by finding seams, or ways to update code without changing existing behavior
• Measuring test coverage and other useful metrics

At the end of this session you will be ready to attack the most monstrous of code bases with TDD.