Kent Beck: Developer Testing

The presentation was recorded at the Developer Testing Forum held in Palo Alto, California, November 17th, 2004.

Kent talks about how the developer tests produced by test-driven development directly contribute to the health of software, and how they can give a developer a sense of accountability without apportioning blame.

The health of software

Kent is interested in developing healthy and quality software emphasising that health is not the same as quality. Health is a continuous measure of the state of software while quality is an instantaneous measure of software at a point in time. Healthy software responds well to stress, e.g. making frequent refactorings and changes to the code. Having automated unit tests helps to make coding changes easier and gives developers courage and confidence to persist.

Developer accountability

Kent talks about the culture of plausible deniability where a developer says "I think this code works" and checks it into the version control repository. In a culture without plausible deniability, the developer is required to prove the code works as expected with developer tests (and automated FIT tests).

Accountability helps to build trust between people - team members, scrum master, customer/product owner, etc. Each developer is individually responsible for the health of the software.

Kent writes developer tests for himself because they make his world run more smoothly while developing and they enable him to think about the design of his code while he's working on it.

Developer Testing


Tags: agile, extreme programming, tdd

posted by Simon Baker @ permalink
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