1 .. SPDX-License-Identifier: GPL-2.0
7 Installing Dependencies
8 =======================
9 KUnit has the same dependencies as the Linux kernel. As long as you can
10 build the kernel, you can run KUnit.
12 Running tests with kunit_tool
13 =============================
14 kunit_tool is a Python script, which configures and builds a kernel, runs
15 tests, and formats the test results. From the kernel repository, you
20 ./tools/testing/kunit/kunit.py run
22 For more information on this wrapper, see:
23 Documentation/dev-tools/kunit/run_wrapper.rst.
25 Creating a ``.kunitconfig``
26 ---------------------------
28 By default, kunit_tool runs a selection of tests. However, you can specify which
29 unit tests to run by creating a ``.kunitconfig`` file with kernel config options
30 that enable only a specific set of tests and their dependencies.
31 The ``.kunitconfig`` file contains a list of kconfig options which are required
32 to run the desired targets. The ``.kunitconfig`` also contains any other test
33 specific config options, such as test dependencies. For example: the
34 ``FAT_FS`` tests - ``FAT_KUNIT_TEST``, depends on
35 ``FAT_FS``. ``FAT_FS`` can be enabled by selecting either ``MSDOS_FS``
36 or ``VFAT_FS``. To run ``FAT_KUNIT_TEST``, the ``.kunitconfig`` has:
42 CONFIG_FAT_KUNIT_TEST=y
44 1. A good starting point for the ``.kunitconfig`` is the KUnit default config.
45 You can generate it by running:
49 cd $PATH_TO_LINUX_REPO
50 tools/testing/kunit/kunit.py config
51 cat .kunit/.kunitconfig
54 ``.kunitconfig`` lives in the ``--build_dir`` used by kunit.py, which is
55 ``.kunit`` by default.
58 You may want to remove CONFIG_KUNIT_ALL_TESTS from the ``.kunitconfig`` as
59 it will enable a number of additional tests that you may not want.
61 2. You can then add any other Kconfig options, for example:
65 CONFIG_LIST_KUNIT_TEST=y
67 Before running the tests, kunit_tool ensures that all config options
68 set in ``.kunitconfig`` are set in the kernel ``.config``. It will warn
69 you if you have not included dependencies for the options used.
72 If you change the ``.kunitconfig``, kunit.py will trigger a rebuild of the
73 ``.config`` file. But you can edit the ``.config`` file directly or with
74 tools like ``make menuconfig O=.kunit``. As long as its a superset of
75 ``.kunitconfig``, kunit.py won't overwrite your changes.
77 Running Tests (KUnit Wrapper)
78 -----------------------------
79 1. To make sure that everything is set up correctly, invoke the Python
80 wrapper from your kernel repository:
84 ./tools/testing/kunit/kunit.py run
86 If everything worked correctly, you should see the following:
90 Generating .config ...
91 Building KUnit Kernel ...
92 Starting KUnit Kernel ...
94 The tests will pass or fail.
97 Because it is building a lot of sources for the first time, the
98 ``Building KUnit kernel`` may take a while.
100 Running Tests without the KUnit Wrapper
101 =======================================
102 If you do not want to use the KUnit Wrapper (for example: you want code
103 under test to integrate with other systems, or use a different/
104 unsupported architecture or configuration), KUnit can be included in
105 any kernel, and the results are read out and parsed manually.
108 ``CONFIG_KUNIT`` should not be enabled in a production environment.
109 Enabling KUnit disables Kernel Address-Space Layout Randomization
110 (KASLR), and tests may affect the state of the kernel in ways not
111 suitable for production.
113 Configuring the Kernel
114 ----------------------
115 To enable KUnit itself, you need to enable the ``CONFIG_KUNIT`` Kconfig
116 option (under Kernel Hacking/Kernel Testing and Coverage in
117 ``menuconfig``). From there, you can enable any KUnit tests. They
118 usually have config options ending in ``_KUNIT_TEST``.
120 KUnit and KUnit tests can be compiled as modules. The tests in a module
121 will run when the module is loaded.
123 Running Tests (without KUnit Wrapper)
124 -------------------------------------
125 Build and run your kernel. In the kernel log, the test output is printed
126 out in the TAP format. This will only happen by default if KUnit/tests
127 are built-in. Otherwise the module will need to be loaded.
130 Some lines and/or data may get interspersed in the TAP output.
132 Writing Your First Test
133 =======================
134 In your kernel repository, let's add some code that we can test.
136 1. Create a file ``drivers/misc/example.h``, which includes:
140 int misc_example_add(int left, int right);
142 2. Create a file ``drivers/misc/example.c``, which includes:
146 #include <linux/errno.h>
150 int misc_example_add(int left, int right)
155 3. Add the following lines to ``drivers/misc/Kconfig``:
157 .. code-block:: kconfig
162 4. Add the following lines to ``drivers/misc/Makefile``:
166 obj-$(CONFIG_MISC_EXAMPLE) += example.o
168 Now we are ready to write the test cases.
170 1. Add the below test case in ``drivers/misc/example_test.c``:
174 #include <kunit/test.h>
177 /* Define the test cases. */
179 static void misc_example_add_test_basic(struct kunit *test)
181 KUNIT_EXPECT_EQ(test, 1, misc_example_add(1, 0));
182 KUNIT_EXPECT_EQ(test, 2, misc_example_add(1, 1));
183 KUNIT_EXPECT_EQ(test, 0, misc_example_add(-1, 1));
184 KUNIT_EXPECT_EQ(test, INT_MAX, misc_example_add(0, INT_MAX));
185 KUNIT_EXPECT_EQ(test, -1, misc_example_add(INT_MAX, INT_MIN));
188 static void misc_example_test_failure(struct kunit *test)
190 KUNIT_FAIL(test, "This test never passes.");
193 static struct kunit_case misc_example_test_cases[] = {
194 KUNIT_CASE(misc_example_add_test_basic),
195 KUNIT_CASE(misc_example_test_failure),
199 static struct kunit_suite misc_example_test_suite = {
200 .name = "misc-example",
201 .test_cases = misc_example_test_cases,
203 kunit_test_suite(misc_example_test_suite);
205 2. Add the following lines to ``drivers/misc/Kconfig``:
207 .. code-block:: kconfig
209 config MISC_EXAMPLE_TEST
210 tristate "Test for my example" if !KUNIT_ALL_TESTS
211 depends on MISC_EXAMPLE && KUNIT=y
212 default KUNIT_ALL_TESTS
214 3. Add the following lines to ``drivers/misc/Makefile``:
218 obj-$(CONFIG_MISC_EXAMPLE_TEST) += example_test.o
220 4. Add the following lines to ``.kunitconfig``:
224 CONFIG_MISC_EXAMPLE=y
225 CONFIG_MISC_EXAMPLE_TEST=y
231 ./tools/testing/kunit/kunit.py run
233 You should see the following failure:
238 [16:08:57] [PASSED] misc-example:misc_example_add_test_basic
239 [16:08:57] [FAILED] misc-example:misc_example_test_failure
240 [16:08:57] EXPECTATION FAILED at drivers/misc/example-test.c:17
241 [16:08:57] This test never passes.
244 Congrats! You just wrote your first KUnit test.
249 * Documentation/dev-tools/kunit/architecture.rst - KUnit architecture.
250 * Documentation/dev-tools/kunit/run_wrapper.rst - run kunit_tool.
251 * Documentation/dev-tools/kunit/run_manual.rst - run tests without kunit_tool.
252 * Documentation/dev-tools/kunit/usage.rst - write tests.
253 * Documentation/dev-tools/kunit/tips.rst - best practices with
255 * Documentation/dev-tools/kunit/api/index.rst - KUnit APIs
257 * Documentation/dev-tools/kunit/kunit-tool.rst - kunit_tool helper
259 * Documentation/dev-tools/kunit/faq.rst - KUnit common questions and