ATF, or Automated Testing Framework, is a collection of libraries to write test programs in C, C++ and POSIX shell.
The ATF libraries offer a simple API. The API is orthogonal through the various bindings, allowing developers to quickly learn how to write test programs in different languages.
ATF-based test programs offer a consistent end-user command-line interface to allow both humans and automation to run the tests.
ATF-based test programs rely on an execution engine to be run and this execution engine is not shipped with ATF. Kyua is the engine of choice.