Unit testing
Unit testing is crucial to ensure that the behavior of your application doesn't unintentionally change over time. Unit tests are going to enable you and your team to continue making changes to your application without introducing changes to previously verified functionality. Developers write unit tests, where each test is scoped to test only the code that exists in the Function Under Test (FUT) or Class Under Test (CUT). Angular components and services are all classes; however, you are also encouraged to develop reusable functions. Unit tests should be plentiful, automated, and fast. You should write unit tests alongside the original code. If they are separated from the implementation, even by a day or two, you are going to start forgetting the details of your code. Because of that, you may forget to write tests for potential edge cases.
Unit tests should adhere to the FIRST principle:
- Fast
- Isolated
- Repeatable
- Self-verifying ...
