The Ultimate Guide to Unit Testing in JavaScript.

A Unit test should test the behavior of a unit of work.

Unit tests are isolated and independent of each other.

Unit tests are lightweight tests:

• Repeatable
• Fast
• Consistent
• Easy to write and read
• Any given behavior should be specified in one and only one test
• The execution/order of execution of one test cannot affect the others

Ultimate Guidelines Which Helped Me a Lot.

• Whenever possible, use TDD
• Structure your tests properly
• Name your tests properly
• Don’t comment out tests
• Avoid logic in your tests
• Don’t write unnecessary expectations
• Know your testing framework API
• Consider using factory functions in the tests
• Don’t test multiple concerns in the same test
• Cover the general case and the edge cases
• Test the behavior, not the internal implementation
• Don’t mock everything