Unit testing with Jest

Testing is an important part of any app. When we refer to tests, we usually mean automated tests. These are tests that we can run in quick repetition to make sure that our code is not broken. When any tests fail, we know that our code did not do what it was doing before. Either we created a bug, or the tests are outdated. Because we can run them quickly, we can write many of them and run them as we build our code.

This is much preferred to manual tests, which must be done by a person doing the same actions over and over again. Manual tests are boring for the tester, they are error-prone, and are very slow. It is just not a pleasant experience for anyone. Therefore, it is better to write as many automated tests as possible to minimize the manual tests.

If the instructions that are shown in the Vue CLI are followed, it is very easy to add skeleton test code without doing any extra work. The files for unit tests should be automatically generated for us. We...