It's important to make the distinction between manual and automated tests. Manual testing is done in person, by clicking through the application or interacting with the software and APIs with the appropriate tooling. This is very expensive since it requires someone to setup an environment and execute the tests themselves, and it can be prone to human error as the tester might make typos or omit steps in the test script.
Automated tests, on the other hand, are performed by a machine that executes a test script that was written in advance. These tests can vary in complexity, from checking a single method in a class to making sure that performing a sequence of complex actions in the UI leads to the same results. It's much more robust and reliable than manual tests – but the quality of your automated tests depends on how well your test scripts have been written. If you're just getting started with testing, you can read our continuous integration tutorial to help you with your first test suite. Looking for more testing tools? Check out these DevOps testing tutorials.
Automated testing is a key component of continuous integration and continuous delivery and it's a great way to scale your QA process as you add new features to your application. But there's still value in doing some manual testing with what is called exploratory testing as we will see in this guide.