Principles and basic concepts of unit testing.
Related presentation material: https://docs.google.com/presentation/d/1yHLEu4tRJ1AKXp_tUAg-N5ZofIkbbcNsTA02Du6dwPA/edit?usp=sharing
- Install npm and node.
- Execute npm init.
- Update package.json
- Add index.html, index.js and index.spec.js