This tutorial focuses on the design and execution of unit tests in COOLAPS applications written in the Logtalk programming language. The tutorial covers the basic setup of the test environment and test definition and examines in detail how this mechanism can be leveraged to find bugs introduced into the code. It also presents coverage of the creation of QuickCheck tests, which is a mechanism for generating large amounts of randomly generated tests from a single definition, and, in so doing, we also cover the advanced notion of property-based testing for AI applications.