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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /Documentation/dev-tools/kunit/start.rst | |
parent | Initial commit. (diff) | |
download | linux-430c2fc249ea5c0536abd21c23382884005c9093.tar.xz linux-430c2fc249ea5c0536abd21c23382884005c9093.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'Documentation/dev-tools/kunit/start.rst')
-rw-r--r-- | Documentation/dev-tools/kunit/start.rst | 237 |
1 files changed, 237 insertions, 0 deletions
diff --git a/Documentation/dev-tools/kunit/start.rst b/Documentation/dev-tools/kunit/start.rst new file mode 100644 index 000000000..454f30781 --- /dev/null +++ b/Documentation/dev-tools/kunit/start.rst @@ -0,0 +1,237 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=============== +Getting Started +=============== + +Installing dependencies +======================= +KUnit has the same dependencies as the Linux kernel. As long as you can build +the kernel, you can run KUnit. + +Running tests with the KUnit Wrapper +==================================== +Included with KUnit is a simple Python wrapper which runs tests under User Mode +Linux, and formats the test results. + +The wrapper can be run with: + +.. code-block:: bash + + ./tools/testing/kunit/kunit.py run + +For more information on this wrapper (also called kunit_tool) check out the +:doc:`kunit-tool` page. + +Creating a .kunitconfig +----------------------- +If you want to run a specific set of tests (rather than those listed in the +KUnit defconfig), you can provide Kconfig options in the ``.kunitconfig`` file. +This file essentially contains the regular Kernel config, with the specific +test targets as well. The ``.kunitconfig`` should also contain any other config +options required by the tests. + +A good starting point for a ``.kunitconfig`` is the KUnit defconfig: + +.. code-block:: bash + + cd $PATH_TO_LINUX_REPO + cp arch/um/configs/kunit_defconfig .kunitconfig + +You can then add any other Kconfig options you wish, e.g.: + +.. code-block:: none + + CONFIG_LIST_KUNIT_TEST=y + +:doc:`kunit_tool <kunit-tool>` will ensure that all config options set in +``.kunitconfig`` are set in the kernel ``.config`` before running the tests. +It'll warn you if you haven't included the dependencies of the options you're +using. + +.. note:: + Note that removing something from the ``.kunitconfig`` will not trigger a + rebuild of the ``.config`` file: the configuration is only updated if the + ``.kunitconfig`` is not a subset of ``.config``. This means that you can use + other tools (such as make menuconfig) to adjust other config options. + + +Running the tests (KUnit Wrapper) +--------------------------------- + +To make sure that everything is set up correctly, simply invoke the Python +wrapper from your kernel repo: + +.. code-block:: bash + + ./tools/testing/kunit/kunit.py run + +.. note:: + You may want to run ``make mrproper`` first. + +If everything worked correctly, you should see the following: + +.. code-block:: bash + + Generating .config ... + Building KUnit Kernel ... + Starting KUnit Kernel ... + +followed by a list of tests that are run. All of them should be passing. + +.. note:: + Because it is building a lot of sources for the first time, the + ``Building KUnit kernel`` step may take a while. + +Running tests without the KUnit Wrapper +======================================= + +If you'd rather not use the KUnit Wrapper (if, for example, you need to +integrate with other systems, or use an architecture other than UML), KUnit can +be included in any kernel, and the results read out and parsed manually. + +.. note:: + KUnit is not designed for use in a production system, and it's possible that + tests may reduce the stability or security of the system. + + + +Configuring the kernel +---------------------- + +In order to enable KUnit itself, you simply need to enable the ``CONFIG_KUNIT`` +Kconfig option (it's under Kernel Hacking/Kernel Testing and Coverage in +menuconfig). From there, you can enable any KUnit tests you want: they usually +have config options ending in ``_KUNIT_TEST``. + +KUnit and KUnit tests can be compiled as modules: in this case the tests in a +module will be run when the module is loaded. + + +Running the tests (w/o KUnit Wrapper) +------------------------------------- + +Build and run your kernel as usual. Test output will be written to the kernel +log in `TAP <https://testanything.org/>`_ format. + +.. note:: + It's possible that there will be other lines and/or data interspersed in the + TAP output. + + +Writing your first test +======================= + +In your kernel repo let's add some code that we can test. Create a file +``drivers/misc/example.h`` with the contents: + +.. code-block:: c + + int misc_example_add(int left, int right); + +create a file ``drivers/misc/example.c``: + +.. code-block:: c + + #include <linux/errno.h> + + #include "example.h" + + int misc_example_add(int left, int right) + { + return left + right; + } + +Now add the following lines to ``drivers/misc/Kconfig``: + +.. code-block:: kconfig + + config MISC_EXAMPLE + bool "My example" + +and the following lines to ``drivers/misc/Makefile``: + +.. code-block:: make + + obj-$(CONFIG_MISC_EXAMPLE) += example.o + +Now we are ready to write the test. The test will be in +``drivers/misc/example-test.c``: + +.. code-block:: c + + #include <kunit/test.h> + #include "example.h" + + /* Define the test cases. */ + + static void misc_example_add_test_basic(struct kunit *test) + { + KUNIT_EXPECT_EQ(test, 1, misc_example_add(1, 0)); + KUNIT_EXPECT_EQ(test, 2, misc_example_add(1, 1)); + KUNIT_EXPECT_EQ(test, 0, misc_example_add(-1, 1)); + KUNIT_EXPECT_EQ(test, INT_MAX, misc_example_add(0, INT_MAX)); + KUNIT_EXPECT_EQ(test, -1, misc_example_add(INT_MAX, INT_MIN)); + } + + static void misc_example_test_failure(struct kunit *test) + { + KUNIT_FAIL(test, "This test never passes."); + } + + static struct kunit_case misc_example_test_cases[] = { + KUNIT_CASE(misc_example_add_test_basic), + KUNIT_CASE(misc_example_test_failure), + {} + }; + + static struct kunit_suite misc_example_test_suite = { + .name = "misc-example", + .test_cases = misc_example_test_cases, + }; + kunit_test_suite(misc_example_test_suite); + +Now add the following to ``drivers/misc/Kconfig``: + +.. code-block:: kconfig + + config MISC_EXAMPLE_TEST + bool "Test for my example" + depends on MISC_EXAMPLE && KUNIT=y + +and the following to ``drivers/misc/Makefile``: + +.. code-block:: make + + obj-$(CONFIG_MISC_EXAMPLE_TEST) += example-test.o + +Now add it to your ``.kunitconfig``: + +.. code-block:: none + + CONFIG_MISC_EXAMPLE=y + CONFIG_MISC_EXAMPLE_TEST=y + +Now you can run the test: + +.. code-block:: bash + + ./tools/testing/kunit/kunit.py run + +You should see the following failure: + +.. code-block:: none + + ... + [16:08:57] [PASSED] misc-example:misc_example_add_test_basic + [16:08:57] [FAILED] misc-example:misc_example_test_failure + [16:08:57] EXPECTATION FAILED at drivers/misc/example-test.c:17 + [16:08:57] This test never passes. + ... + +Congrats! You just wrote your first KUnit test! + +Next Steps +========== +* Check out the :doc:`usage` page for a more + in-depth explanation of KUnit. |