Coverage helps us see what part of our app is covered with tests and can help us determine if new code is covered in pull requests with tools such as SonarQube or Coveralls. My recommended testing strategy for testing Angular apps is to focus on covering the use cases with Cypress component tests and add some unit tests around edge cases and calculation while having a few e2e tests as a smoke test thus needing to combine test coverage from all these different sources to get a clear picture of what code is tested.

Getting coverage for Jest comes out of the box but setting up coverage with Cypress E2E and component tests and merging the coverage results all together requires more manual intervention and this blog post is covering how to get coverage from the different testing techniques and combine the coverage results into one report in an Nx project.

You can read the post here.