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======================
Linux Kernel Selftests
======================
The kernel contains a set of "self tests" under the tools/testing/selftests/
directory. These are intended to be small tests to exercise individual code
paths in the kernel. Tests are intended to be run after building, installing
and booting a kernel.
On some systems, hot-plug tests could hang forever waiting for cpu and
memory to be ready to be offlined. A special hot-plug target is created
to run full range of hot-plug tests. In default mode, hot-plug tests run
in safe mode with a limited scope. In limited mode, cpu-hotplug test is
run on a single cpu as opposed to all hotplug capable cpus, and memory
hotplug test is run on 2% of hotplug capable memory instead of 10%.
Running the selftests (hotplug tests are run in limited mode)
=============================================================
To build the tests::
$ make -C tools/testing/selftests
To run the tests::
$ make -C tools/testing/selftests run_tests
To build and run the tests with a single command, use::
$ make kselftest
Note that some tests will require root privileges.
Build and run from user specific object directory (make O=dir)::
$ make O=/tmp/kselftest kselftest
Build and run KBUILD_OUTPUT directory (make KBUILD_OUTPUT=)::
$ make KBUILD_OUTPUT=/tmp/kselftest kselftest
The above commands run the tests and print pass/fail summary to make it
easier to understand the test results. Please find the detailed individual
test results for each test in /tmp/testname file(s).
Running a subset of selftests
=============================
You can use the "TARGETS" variable on the make command line to specify
single test to run, or a list of tests to run.
To run only tests targeted for a single subsystem::
$ make -C tools/testing/selftests TARGETS=ptrace run_tests
You can specify multiple tests to build and run::
$ make TARGETS="size timers" kselftest
Build and run from user specific object directory (make O=dir)::
$ make O=/tmp/kselftest TARGETS="size timers" kselftest
Build and run KBUILD_OUTPUT directory (make KBUILD_OUTPUT=)::
$ make KBUILD_OUTPUT=/tmp/kselftest TARGETS="size timers" kselftest
The above commands run the tests and print pass/fail summary to make it
easier to understand the test results. Please find the detailed individual
test results for each test in /tmp/testname file(s).
See the top-level tools/testing/selftests/Makefile for the list of all
possible targets.
Running the full range hotplug selftests
========================================
To build the hotplug tests::
$ make -C tools/testing/selftests hotplug
To run the hotplug tests::
$ make -C tools/testing/selftests run_hotplug
Note that some tests will require root privileges.
Install selftests
=================
You can use kselftest_install.sh tool installs selftests in default
location which is tools/testing/selftests/kselftest or a user specified
location.
To install selftests in default location::
$ cd tools/testing/selftests
$ ./kselftest_install.sh
To install selftests in a user specified location::
$ cd tools/testing/selftests
$ ./kselftest_install.sh install_dir
Running installed selftests
===========================
Kselftest install as well as the Kselftest tarball provide a script
named "run_kselftest.sh" to run the tests.
You can simply do the following to run the installed KselftestsPlease
note some tests will require root privileges::
$ cd kselftest
$ ./run_kselftest.sh
Contributing new tests
======================
In general, the rules for selftests are
* Do as much as you can if you're not root;
* Don't take too long;
* Don't break the build on any architecture, and
* Don't cause the top-level "make run_tests" to fail if your feature is
unconfigured.
Contributing new tests (details)
================================
* Use TEST_GEN_XXX if such binaries or files are generated during
compiling.
TEST_PROGS, TEST_GEN_PROGS mean it is the executable tested by
default.
TEST_CUSTOM_PROGS should be used by tests that require custom build
rule and prevent common build rule use.
TEST_PROGS are for test shell scripts. Please ensure shell script has
its exec bit set. Otherwise, lib.mk run_tests will generate a warning.
TEST_CUSTOM_PROGS and TEST_PROGS will be run by common run_tests.
TEST_PROGS_EXTENDED, TEST_GEN_PROGS_EXTENDED mean it is the
executable which is not tested by default.
TEST_FILES, TEST_GEN_FILES mean it is the file which is used by
test.
Test Harness
============
The kselftest_harness.h file contains useful helpers to build tests. The tests
from tools/testing/selftests/seccomp/seccomp_bpf.c can be used as example.
Example
-------
.. kernel-doc:: tools/testing/selftests/kselftest_harness.h
:doc: example
Helpers
-------
.. kernel-doc:: tools/testing/selftests/kselftest_harness.h
:functions: TH_LOG TEST TEST_SIGNAL FIXTURE FIXTURE_DATA FIXTURE_SETUP
FIXTURE_TEARDOWN TEST_F TEST_HARNESS_MAIN
Operators
---------
.. kernel-doc:: tools/testing/selftests/kselftest_harness.h
:doc: operators
.. kernel-doc:: tools/testing/selftests/kselftest_harness.h
:functions: ASSERT_EQ ASSERT_NE ASSERT_LT ASSERT_LE ASSERT_GT ASSERT_GE
ASSERT_NULL ASSERT_TRUE ASSERT_NULL ASSERT_TRUE ASSERT_FALSE
ASSERT_STREQ ASSERT_STRNE EXPECT_EQ EXPECT_NE EXPECT_LT
EXPECT_LE EXPECT_GT EXPECT_GE EXPECT_NULL EXPECT_TRUE
EXPECT_FALSE EXPECT_STREQ EXPECT_STRNE