Efficient Node.js

Chapter 8. Testing Node

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Testing in the real world is generally about finding what’s wrong with something. When it comes to code, testing is about finding what’s right. It’s the guarantee that something is working.

Untested code is simply dangerous. Efficient and scalable code is well-tested. Testing is not only about making sure the code is doing what it is supposed to do, it’s also about making sure the code continues to do what it is supposed to do after any changes in the code, its environment, and its use patterns. Testing is about writing high quality code and catching potential problems as early as possible.

Regular testing of code keeps it healthy and makes maintaining it easier. It also increases the confidence of its maintainers to make changes. Making changes to untested code is a recipe for disaster. A new feature in module X might break other features in module Y. You can’t keep the dependencies in your head. You ...