This is a great comment. As a small addition to this, a good technique to assess if your unit tests are able to catch behavior changes in an application when th

This is a great comment. As a small addition to this, a good technique to assess if your unit tests are able to catch behavior changes in an application when the code changes is Mutation Testing. This is a small explanation and demo I made recently with Stryker, a framework for the JavaScript ecosystem https://github.com/peter-evans/mutation-testing https://github.com/peter-evans/mutation-testing This is a good list of available frameworks in other languages: https://github.com/theofidry/awesome-mutation-testing https://github.com/theofidry/awesome-mutation-testing