docs: python: add helpers to run unit tests

docs: python: add helpers to run unit tests

While python internal libraries have support for unit tests, its
output is not nice. Add a helper module to improve its output.

I wrote this module last year while testing some scripts I used
internally. The initial skeleton was generated with the help of
LLM tools, but it was higly modified to ensure that it will work
as I would expect.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Message-ID: <37999041f616ddef41e84cf2686c0264d1a51dc9.1773074166.git.mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <d81be167b8cdeb003c1f8dcc7ad83a5ed2b520b6.1773770483.git.mchehab+huawei@kernel.org>