1.. SPDX-License-Identifier: GPL-2.0 2 3============================= 4Running tests with kunit_tool 5============================= 6 7We can either run KUnit tests using kunit_tool or can run tests 8manually, and then use kunit_tool to parse the results. To run tests 9manually, see: Documentation/dev-tools/kunit/run_manual.rst. 10As long as we can build the kernel, we can run KUnit. 11 12kunit_tool is a Python script which configures and builds a kernel, runs 13tests, and formats the test results. 14 15Run command: 16 17.. code-block:: 18 19 ./tools/testing/kunit/kunit.py run 20 21We should see the following: 22 23.. code-block:: 24 25 Configuring KUnit Kernel ... 26 Building KUnit kernel... 27 Starting KUnit kernel... 28 29We may want to use the following options: 30 31.. code-block:: 32 33 ./tools/testing/kunit/kunit.py run --timeout=30 --jobs=`nproc --all` 34 35- ``--timeout`` sets a maximum amount of time for tests to run. 36- ``--jobs`` sets the number of threads to build the kernel. 37 38kunit_tool will generate a ``.kunitconfig`` with a default 39configuration, if no other ``.kunitconfig`` file exists 40(in the build directory). In addition, it verifies that the 41generated ``.config`` file contains the ``CONFIG`` options in the 42``.kunitconfig``. 43It is also possible to pass a separate ``.kunitconfig`` fragment to 44kunit_tool. This is useful if we have several different groups of 45tests we want to run independently, or if we want to use pre-defined 46test configs for certain subsystems. 47 48To use a different ``.kunitconfig`` file (such as one 49provided to test a particular subsystem), pass it as an option: 50 51.. code-block:: 52 53 ./tools/testing/kunit/kunit.py run --kunitconfig=fs/ext4/.kunitconfig 54 55To view kunit_tool flags (optional command-line arguments), run: 56 57.. code-block:: 58 59 ./tools/testing/kunit/kunit.py run --help 60 61Creating a ``.kunitconfig`` file 62================================ 63 64If we want to run a specific set of tests (rather than those listed 65in the KUnit ``defconfig``), we can provide Kconfig options in the 66``.kunitconfig`` file. For default .kunitconfig, see: 67https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/testing/kunit/configs/default.config. 68A ``.kunitconfig`` is a ``minconfig`` (a .config 69generated by running ``make savedefconfig``), used for running a 70specific set of tests. This file contains the regular Kernel configs 71with specific test targets. The ``.kunitconfig`` also 72contains any other config options required by the tests (For example: 73dependencies for features under tests, configs that enable/disable 74certain code blocks, arch configs and so on). 75 76To create a ``.kunitconfig``, using the KUnit ``defconfig``: 77 78.. code-block:: 79 80 cd $PATH_TO_LINUX_REPO 81 cp tools/testing/kunit/configs/default.config .kunit/.kunitconfig 82 83We can then add any other Kconfig options. For example: 84 85.. code-block:: 86 87 CONFIG_LIST_KUNIT_TEST=y 88 89kunit_tool ensures that all config options in ``.kunitconfig`` are 90set in the kernel ``.config`` before running the tests. It warns if we 91have not included the options dependencies. 92 93.. note:: Removing something from the ``.kunitconfig`` will 94 not rebuild the ``.config file``. The configuration is only 95 updated if the ``.kunitconfig`` is not a subset of ``.config``. 96 This means that we can use other tools 97 (For example: ``make menuconfig``) to adjust other config options. 98 The build dir needs to be set for ``make menuconfig`` to 99 work, therefore by default use ``make O=.kunit menuconfig``. 100 101Configuring, building, and running tests 102======================================== 103 104If we want to make manual changes to the KUnit build process, we 105can run part of the KUnit build process independently. 106When running kunit_tool, from a ``.kunitconfig``, we can generate a 107``.config`` by using the ``config`` argument: 108 109.. code-block:: 110 111 ./tools/testing/kunit/kunit.py config 112 113To build a KUnit kernel from the current ``.config``, we can use the 114``build`` argument: 115 116.. code-block:: 117 118 ./tools/testing/kunit/kunit.py build 119 120If we already have built UML kernel with built-in KUnit tests, we 121can run the kernel, and display the test results with the ``exec`` 122argument: 123 124.. code-block:: 125 126 ./tools/testing/kunit/kunit.py exec 127 128The ``run`` command discussed in section: **Running tests with kunit_tool**, 129is equivalent to running the above three commands in sequence. 130 131Parsing test results 132==================== 133 134KUnit tests output displays results in TAP (Test Anything Protocol) 135format. When running tests, kunit_tool parses this output and prints 136a summary. To see the raw test results in TAP format, we can pass the 137``--raw_output`` argument: 138 139.. code-block:: 140 141 ./tools/testing/kunit/kunit.py run --raw_output 142 143If we have KUnit results in the raw TAP format, we can parse them and 144print the human-readable summary with the ``parse`` command for 145kunit_tool. This accepts a filename for an argument, or will read from 146standard input. 147 148.. code-block:: bash 149 150 # Reading from a file 151 ./tools/testing/kunit/kunit.py parse /var/log/dmesg 152 # Reading from stdin 153 dmesg | ./tools/testing/kunit/kunit.py parse 154 155Filtering tests 156=============== 157 158By passing a bash style glob filter to the ``exec`` or ``run`` 159commands, we can run a subset of the tests built into a kernel . For 160example: if we only want to run KUnit resource tests, use: 161 162.. code-block:: 163 164 ./tools/testing/kunit/kunit.py run 'kunit-resource*' 165 166This uses the standard glob format with wildcard characters. 167 168.. _kunit-on-qemu: 169 170Running tests on QEMU 171===================== 172 173kunit_tool supports running tests on qemu as well as 174via UML. To run tests on qemu, by default it requires two flags: 175 176- ``--arch``: Selects a configs collection (Kconfig, qemu config options 177 and so on), that allow KUnit tests to be run on the specified 178 architecture in a minimal way. The architecture argument is same as 179 the option name passed to the ``ARCH`` variable used by Kbuild. 180 Not all architectures currently support this flag, but we can use 181 ``--qemu_config`` to handle it. If ``um`` is passed (or this flag 182 is ignored), the tests will run via UML. Non-UML architectures, 183 for example: i386, x86_64, arm and so on; run on qemu. 184 185 ``--arch help`` lists all valid ``--arch`` values. 186 187- ``--cross_compile``: Specifies the Kbuild toolchain. It passes the 188 same argument as passed to the ``CROSS_COMPILE`` variable used by 189 Kbuild. As a reminder, this will be the prefix for the toolchain 190 binaries such as GCC. For example: 191 192 - ``sparc64-linux-gnu`` if we have the sparc toolchain installed on 193 our system. 194 195 - ``$HOME/toolchains/microblaze/gcc-9.2.0-nolibc/microblaze-linux/bin/microblaze-linux`` 196 if we have downloaded the microblaze toolchain from the 0-day 197 website to a directory in our home directory called toolchains. 198 199This means that for most architectures, running under qemu is as simple as: 200 201.. code-block:: bash 202 203 ./tools/testing/kunit/kunit.py run --arch=x86_64 204 205When cross-compiling, we'll likely need to specify a different toolchain, for 206example: 207 208.. code-block:: bash 209 210 ./tools/testing/kunit/kunit.py run \ 211 --arch=s390 \ 212 --cross_compile=s390x-linux-gnu- 213 214If we want to run KUnit tests on an architecture not supported by 215the ``--arch`` flag, or want to run KUnit tests on qemu using a 216non-default configuration; then we can write our own``QemuConfig``. 217These ``QemuConfigs`` are written in Python. They have an import line 218``from..qemu_config import QemuArchParams`` at the top of the file. 219The file must contain a variable called ``QEMU_ARCH`` that has an 220instance of ``QemuArchParams`` assigned to it. See example in: 221``tools/testing/kunit/qemu_configs/x86_64.py``. 222 223Once we have a ``QemuConfig``, we can pass it into kunit_tool, 224using the ``--qemu_config`` flag. When used, this flag replaces the 225``--arch`` flag. For example: using 226``tools/testing/kunit/qemu_configs/x86_64.py``, the invocation appear 227as 228 229.. code-block:: bash 230 231 ./tools/testing/kunit/kunit.py run \ 232 --timeout=60 \ 233 --jobs=12 \ 234 --qemu_config=./tools/testing/kunit/qemu_configs/x86_64.py 235 236Running command-line arguments 237============================== 238 239kunit_tool has a number of other command-line arguments which can 240be useful for our test environment. Below are the most commonly used 241command line arguments: 242 243- ``--help``: Lists all available options. To list common options, 244 place ``--help`` before the command. To list options specific to that 245 command, place ``--help`` after the command. 246 247 .. note:: Different commands (``config``, ``build``, ``run``, etc) 248 have different supported options. 249- ``--build_dir``: Specifies kunit_tool build directory. It includes 250 the ``.kunitconfig``, ``.config`` files and compiled kernel. 251 252- ``--make_options``: Specifies additional options to pass to make, when 253 compiling a kernel (using ``build`` or ``run`` commands). For example: 254 to enable compiler warnings, we can pass ``--make_options W=1``. 255 256- ``--alltests``: Enable a predefined set of options in order to build 257 as many tests as possible. 258 259 .. note:: The list of enabled options can be found in 260 ``tools/testing/kunit/configs/all_tests.config``. 261 262 If you only want to enable all tests with otherwise satisfied 263 dependencies, instead add ``CONFIG_KUNIT_ALL_TESTS=y`` to your 264 ``.kunitconfig``. 265 266- ``--kunitconfig``: Specifies the path or the directory of the ``.kunitconfig`` 267 file. For example: 268 269 - ``lib/kunit/.kunitconfig`` can be the path of the file. 270 271 - ``lib/kunit`` can be the directory in which the file is located. 272 273 This file is used to build and run with a predefined set of tests 274 and their dependencies. For example, to run tests for a given subsystem. 275 276- ``--kconfig_add``: Specifies additional configuration options to be 277 appended to the ``.kunitconfig`` file. For example: 278 279 .. code-block:: 280 281 ./tools/testing/kunit/kunit.py run --kconfig_add CONFIG_KASAN=y 282 283- ``--arch``: Runs tests on the specified architecture. The architecture 284 argument is same as the Kbuild ARCH environment variable. 285 For example, i386, x86_64, arm, um, etc. Non-UML architectures run on qemu. 286 Default is `um`. 287 288- ``--cross_compile``: Specifies the Kbuild toolchain. It passes the 289 same argument as passed to the ``CROSS_COMPILE`` variable used by 290 Kbuild. This will be the prefix for the toolchain 291 binaries such as GCC. For example: 292 293 - ``sparc64-linux-gnu-`` if we have the sparc toolchain installed on 294 our system. 295 296 - ``$HOME/toolchains/microblaze/gcc-9.2.0-nolibc/microblaze-linux/bin/microblaze-linux`` 297 if we have downloaded the microblaze toolchain from the 0-day 298 website to a specified path in our home directory called toolchains. 299 300- ``--qemu_config``: Specifies the path to a file containing a 301 custom qemu architecture definition. This should be a python file 302 containing a `QemuArchParams` object. 303 304- ``--qemu_args``: Specifies additional qemu arguments, for example, ``-smp 8``. 305 306- ``--jobs``: Specifies the number of jobs (commands) to run simultaneously. 307 By default, this is set to the number of cores on your system. 308 309- ``--timeout``: Specifies the maximum number of seconds allowed for all tests to run. 310 This does not include the time taken to build the tests. 311 312- ``--kernel_args``: Specifies additional kernel command-line arguments. May be repeated. 313 314- ``--run_isolated``: If set, boots the kernel for each individual suite/test. 315 This is useful for debugging a non-hermetic test, one that 316 might pass/fail based on what ran before it. 317 318- ``--raw_output``: If set, generates unformatted output from kernel. Possible options are: 319 320 - ``all``: To view the full kernel output, use ``--raw_output=all``. 321 322 - ``kunit``: This is the default option and filters to KUnit output. Use ``--raw_output`` or ``--raw_output=kunit``. 323 324- ``--json``: If set, stores the test results in a JSON format and prints to `stdout` or 325 saves to a file if a filename is specified. 326 327- ``--filter``: Specifies filters on test attributes, for example, ``speed!=slow``. 328 Multiple filters can be used by wrapping input in quotes and separating filters 329 by commas. Example: ``--filter "speed>slow, module=example"``. 330 331- ``--filter_action``: If set to ``skip``, filtered tests will be shown as skipped 332 in the output rather than showing no output. 333 334- ``--list_tests``: If set, lists all tests that will be run. 335 336- ``--list_tests_attr``: If set, lists all tests that will be run and all of their 337 attributes. 338