Testing is one of the essential parts of the development cycle. Testing ensures that bug-free and secure code is deployed to the higher environment, and we should make sure that the testing should be automated as much as possible. Testing should be combined with the continuous integration process and eventually with continuous deployment. The benefit of testing is that it saves lots time and money for organizations because it mitigates most of the bugs and errors at the initial stage of development. There are many different levels of testing, such as unit testing, integration testing, functional testing, and performance testing. Let's look at the best practices around these levels.