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.. SPDX-License-Identifier: GPL-2.0
=================
kunit_tool How-To
=================
What is kunit_tool?
===================
kunit_tool is a script (``tools/testing/kunit/kunit.py``) that aids in building
the Linux kernel as UML (`User Mode Linux
<http://user-mode-linux.sourceforge.net/>`_), running KUnit tests, parsing
the test results and displaying them in a user friendly manner.
kunit_tool addresses the problem of being able to run tests without needing a
virtual machine or actual hardware with User Mode Linux. User Mode Linux is a
Linux architecture, like ARM or x86; however, unlike other architectures it
compiles the kernel as a standalone Linux executable that can be run like any
other program directly inside of a host operating system. To be clear, it does
not require any virtualization support: it is just a regular program.
What is a kunitconfig?
======================
It's just a defconfig that kunit_tool looks for in the base directory.
kunit_tool uses it to generate a .config as you might expect. In addition, it
verifies that the generated .config contains the CONFIG options in the
kunitconfig; the reason it does this is so that it is easy to be sure that a
CONFIG that enables a test actually ends up in the .config.
How do I use kunit_tool?
========================
If a kunitconfig is present at the root directory, all you have to do is:
.. code-block:: bash
./tools/testing/kunit/kunit.py run
However, you most likely want to use it with the following options:
.. code-block:: bash
./tools/testing/kunit/kunit.py run --timeout=30 --jobs=`nproc --all`
- ``--timeout`` sets a maximum amount of time to allow tests to run.
- ``--jobs`` sets the number of threads to use to build the kernel.
If you just want to use the defconfig that ships with the kernel, you can
append the ``--defconfig`` flag as well:
.. code-block:: bash
./tools/testing/kunit/kunit.py run --timeout=30 --jobs=`nproc --all` --defconfig
.. note::
This command is particularly helpful for getting started because it
just works. No kunitconfig needs to be present.
For a list of all the flags supported by kunit_tool, you can run:
.. code-block:: bash
./tools/testing/kunit/kunit.py run --help