Kent Beck’s Four Rules of Software Design (also known as “Simple Design”)

For the first time in many years I just came across Kent Beck’s Four Rules of Software Design:

1. Passes the tests
2. Reveals intention (should be easy to understand)
3. No duplication (DRY)
4. Fewest elements (remove anything that doesn’t serve the three previous rules)

There are wording variations on those rules, but I got those specific words from this Martin Fowler post. As he notes, “The rules are in priority order, so ‘passes the tests’ takes priority over ‘reveals intention.’”

For more information on Kent Beck’s Four Rules of Software Design, see that link, or this link to the original rules on c2.com.