Testing automation
Whatever testing you are doing manually can be automated and made part of the build. This means that any change or code commit will run the test suite as a part of the build. A build will only be successful if all the tests are passed.
You can add automated integration tests for all the APIs. So, instead of firing each API manually using cURL or Insomnia, the build will fire them, and the test result will be available at the end of the build.
In this section, you are going to write an integration test that will replicate the REST client call and test all the application layers, starting from the controller, all the way down to the persistence layer, including the database (H2).
But before that, you will add the necessary unit tests. Ideally, these unit tests should have been added alongside the development process, or before the development process in the case of test-driven development (TDD).
Unit tests are tests that validate the expected results of...