Testing can be done manually, as we have done with the AWS Management Console, which is prone to error and not scalable. Generally, tests are automated using test suites, which are written in advance and are essential for continuous integration and continuous delivery.

There are many definitions and types of software testing available; it could take a whole book to cover them all. Here, we will focus on the three main ones that are relevant for our serverless stacks:

• Unit testing: The low-level testing of individual software modules in isolation, typically done by the developers and used in test-driven development (TDD). These types of tests are usually quick to execute.
• Integration testing: Verifies that all combined services after integration are working correctly. These are generally more expensive to run as many services need to be running.
• Load testing: This is non-functional testing used to check how the system performs under a heavy load. It is sometimes also called performance or stress testing as it helps to understand the availability and reliability of a platform.