.. 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 `_), 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. .. note:: This command will work even without a .kunitconfig file: if no .kunitconfig is present, a default one will be used instead. For a list of all the flags supported by kunit_tool, you can run: .. code-block:: bash ./tools/testing/kunit/kunit.py run --help