Acceptance test library (ATL) resources 

The Acceptance test library (ATL) is an X++ test library that offers the following benefits:

The structure and names of the classes and methods in ATL are quite rigid. This rigidity helps improve discoverability and also makes it easier to write tests, even in domains that you're unfamiliar with.

The classes are grouped into the following concepts:

To learn more about ATL, please refer to https://docs.microsoft.com/en-gb/dynamics365/unified-operations/dev-itpro/perf-test/acceptance-test-library#example-of-a-test-that-is-written-in-atl.