We already know that good unit tests are on FIRE. Here are some characteristics of good code:

Small – Classes contain only a few methods. Methods are no more than a few lines. Together they fit nicely on your screen without scrolling.

Intentional – Every bit of your code reveals precisely why it is there and what you intend for it to do.

Singular – Classes have one responsibility. Methods do one thing.

Tested – Every piece of interesting behavior in your code has a corresponding test (Likely it was written first.)

Encapsulated – Modules don’t know what information other modules contain. They tell instead of asking. They talk only to their closest collaborators.

Refactored – Eventually, code has to change. Good code stays good when it changes because it’s author loves it.