At the most basic level, there's the Test APIs which you should use when
writing tests in Python and planning to make use of any other utility library.

The Test APIs can be found in the :mod:`avocado` main module and its most
important member is the :class:`avocado.Test` class. By conforming to the
:class:`avocado.Test` API, that is, by inheriting from it, you can use the full
set of utility libraries.

The Test APIs are guaranteed to be stable across a single major version of
Avocado.  That means that a test written for a given version of Avocado should
not break on later minor versions because of Test API changes.

This is the bare mininum set of APIs that users should use, and can rely on,
while writing tests.
