Automated testing greatly helps in making the system bug-free, even after adding new functionalities. JHipster creates unit and integration test cases for generated code that will be helpful up to some extent. In a real scenario, we need to add further unit test cases targeted for custom business implementations; for example, you might have added few custom screens, controller and service layer for which you need to write additional unit test cases. 

Also, we need to add integration test cases for newly introduced APIs. Apart from that, we also need to add client-side test cases for frontend customization.

Presently, testing and continuous integration have become an integral part of the software development process. Testing will help to produce a quality product, while continuous integration is nothing but constantly merging and testing newly introduced code changes, which assists in identifying potential bugs. This happens with the combination of executing automated units, integration, and end-to-end test cases against the code. A classic example is triggering the automated test suite on every commit on Git; or, more efficiently, running it as per a predefined schedule.

The benefits of an automated testing model can be achieved by putting a continuous integration process in place, to make sure that new code changes do not introduce regressions to the stable version. This assures the merging of new changes and deploying to production with confidence.

The continuous testing, integration, and continuous deployment results in a concept called Continuous Integration/Continuous Deployment (CI/CD), which performs continuous integration, testing, and deploying the code. Continuous delivery can be achieved through various CI/CD tools. JHipster provides elegant support for well known CI/CD tools available in the market today, such as Jenkins, Travis CI, GitLab CI, and Circle CI.