Agile in a Flash 48

Refactoring Inhibitors – The Code

Agile in a Flash by Jeff Langr and Tim Ottinger (card #48)

> Insufficient tests

> Long-lived branches

> Implementation-specific tests

> Crushing technical debt

> No know-how

> Premature performance infatuation

> Management metric mandates

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Agile’s demand for continual change can rapidly degrade a system’s design. Refactoring is essential to keeping maintenance costs low in an agile environment.

Insufficient tests. TDD gives you the confidence to refactor and do the right thing, when you would not otherwise for fear of breaking existing code.

Long-lived branches. Working on a branch, you’ll plead for minimal trunk refactoring in order to avoid merge hell. Most branches should be short-lived.

Implementation-specific tests. You may want to discard tests, ultimately killing refactoring, if small refactorings breaks many tests at once. Minimize testto-System Under Test (SUT) encapsulation violations, which mocks can create.

Crushing technical debt. Insufficient refactoring creates overwhelming rampant duplication and difficult code. Refactor on every green to minimize debt.

No know-how. You can’t refactor if you don’t know which direction to take the code. Learn all you can about design, starting with simple design.

Premature performance infatuation. Don’t let baseless performance fear stifle cohesive designs. Make it run, make it right, and only then make it fast.

Management metric mandates. Governance by often one-dimensional and insufficient metrics (such as increase coverage) can discourage refactoring.

-- Do not assume you wrote good code or did good refactoring. Test, Test and then test again.