197 строки
8.0 KiB
ReStructuredText
197 строки
8.0 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0
|
|
|
|
==================
|
|
KUnit Architecture
|
|
==================
|
|
|
|
The KUnit architecture is divided into two parts:
|
|
|
|
- `In-Kernel Testing Framework`_
|
|
- `kunit_tool (Command-line Test Harness)`_
|
|
|
|
In-Kernel Testing Framework
|
|
===========================
|
|
|
|
The kernel testing library supports KUnit tests written in C using
|
|
KUnit. These KUnit tests are kernel code. KUnit performs the following
|
|
tasks:
|
|
|
|
- Organizes tests
|
|
- Reports test results
|
|
- Provides test utilities
|
|
|
|
Test Cases
|
|
----------
|
|
|
|
The test case is the fundamental unit in KUnit. KUnit test cases are organised
|
|
into suites. A KUnit test case is a function with type signature
|
|
``void (*)(struct kunit *test)``. These test case functions are wrapped in a
|
|
struct called struct kunit_case.
|
|
|
|
.. note:
|
|
``generate_params`` is optional for non-parameterized tests.
|
|
|
|
Each KUnit test case receives a ``struct kunit`` context object that tracks a
|
|
running test. The KUnit assertion macros and other KUnit utilities use the
|
|
``struct kunit`` context object. As an exception, there are two fields:
|
|
|
|
- ``->priv``: The setup functions can use it to store arbitrary test
|
|
user data.
|
|
|
|
- ``->param_value``: It contains the parameter value which can be
|
|
retrieved in the parameterized tests.
|
|
|
|
Test Suites
|
|
-----------
|
|
|
|
A KUnit suite includes a collection of test cases. The KUnit suites
|
|
are represented by the ``struct kunit_suite``. For example:
|
|
|
|
.. code-block:: c
|
|
|
|
static struct kunit_case example_test_cases[] = {
|
|
KUNIT_CASE(example_test_foo),
|
|
KUNIT_CASE(example_test_bar),
|
|
KUNIT_CASE(example_test_baz),
|
|
{}
|
|
};
|
|
|
|
static struct kunit_suite example_test_suite = {
|
|
.name = "example",
|
|
.init = example_test_init,
|
|
.exit = example_test_exit,
|
|
.test_cases = example_test_cases,
|
|
};
|
|
kunit_test_suite(example_test_suite);
|
|
|
|
In the above example, the test suite ``example_test_suite``, runs the
|
|
test cases ``example_test_foo``, ``example_test_bar``, and
|
|
``example_test_baz``. Before running the test, the ``example_test_init``
|
|
is called and after running the test, ``example_test_exit`` is called.
|
|
The ``kunit_test_suite(example_test_suite)`` registers the test suite
|
|
with the KUnit test framework.
|
|
|
|
Executor
|
|
--------
|
|
|
|
The KUnit executor can list and run built-in KUnit tests on boot.
|
|
The Test suites are stored in a linker section
|
|
called ``.kunit_test_suites``. For the code, see ``KUNIT_TABLE()`` macro
|
|
definition in
|
|
`include/asm-generic/vmlinux.lds.h <https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/asm-generic/vmlinux.lds.h?h=v6.0#n950>`_.
|
|
The linker section consists of an array of pointers to
|
|
``struct kunit_suite``, and is populated by the ``kunit_test_suites()``
|
|
macro. The KUnit executor iterates over the linker section array in order to
|
|
run all the tests that are compiled into the kernel.
|
|
|
|
.. kernel-figure:: kunit_suitememorydiagram.svg
|
|
:alt: KUnit Suite Memory
|
|
|
|
KUnit Suite Memory Diagram
|
|
|
|
On the kernel boot, the KUnit executor uses the start and end addresses
|
|
of this section to iterate over and run all tests. For the implementation of the
|
|
executor, see
|
|
`lib/kunit/executor.c <https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/lib/kunit/executor.c>`_.
|
|
When built as a module, the ``kunit_test_suites()`` macro defines a
|
|
``module_init()`` function, which runs all the tests in the compilation
|
|
unit instead of utilizing the executor.
|
|
|
|
In KUnit tests, some error classes do not affect other tests
|
|
or parts of the kernel, each KUnit case executes in a separate thread
|
|
context. See the ``kunit_try_catch_run()`` function in
|
|
`lib/kunit/try-catch.c <https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/lib/kunit/try-catch.c?h=v5.15#n58>`_.
|
|
|
|
Assertion Macros
|
|
----------------
|
|
|
|
KUnit tests verify state using expectations/assertions.
|
|
All expectations/assertions are formatted as:
|
|
``KUNIT_{EXPECT|ASSERT}_<op>[_MSG](kunit, property[, message])``
|
|
|
|
- ``{EXPECT|ASSERT}`` determines whether the check is an assertion or an
|
|
expectation.
|
|
In the event of a failure, the testing flow differs as follows:
|
|
|
|
- For expectations, the test is marked as failed and the failure is logged.
|
|
|
|
- Failing assertions, on the other hand, result in the test case being
|
|
terminated immediately.
|
|
|
|
- Assertions call the function:
|
|
``void __noreturn kunit_abort(struct kunit *)``.
|
|
|
|
- ``kunit_abort`` calls the function:
|
|
``void __noreturn kunit_try_catch_throw(struct kunit_try_catch *try_catch)``.
|
|
|
|
- ``kunit_try_catch_throw`` calls the function:
|
|
``void kthread_complete_and_exit(struct completion *, long) __noreturn;``
|
|
and terminates the special thread context.
|
|
|
|
- ``<op>`` denotes a check with options: ``TRUE`` (supplied property
|
|
has the boolean value "true"), ``EQ`` (two supplied properties are
|
|
equal), ``NOT_ERR_OR_NULL`` (supplied pointer is not null and does not
|
|
contain an "err" value).
|
|
|
|
- ``[_MSG]`` prints a custom message on failure.
|
|
|
|
Test Result Reporting
|
|
---------------------
|
|
KUnit prints the test results in KTAP format. KTAP is based on TAP14, see
|
|
Documentation/dev-tools/ktap.rst.
|
|
KTAP works with KUnit and Kselftest. The KUnit executor prints KTAP results to
|
|
dmesg, and debugfs (if configured).
|
|
|
|
Parameterized Tests
|
|
-------------------
|
|
|
|
Each KUnit parameterized test is associated with a collection of
|
|
parameters. The test is invoked multiple times, once for each parameter
|
|
value and the parameter is stored in the ``param_value`` field.
|
|
The test case includes a KUNIT_CASE_PARAM() macro that accepts a
|
|
generator function. The generator function is passed the previous parameter
|
|
and returns the next parameter. It also includes a macro for generating
|
|
array-based common-case generators.
|
|
|
|
kunit_tool (Command-line Test Harness)
|
|
======================================
|
|
|
|
``kunit_tool`` is a Python script, found in ``tools/testing/kunit/kunit.py``. It
|
|
is used to configure, build, execute, parse test results and run all of the
|
|
previous commands in correct order (i.e., configure, build, execute and parse).
|
|
You have two options for running KUnit tests: either build the kernel with KUnit
|
|
enabled and manually parse the results (see
|
|
Documentation/dev-tools/kunit/run_manual.rst) or use ``kunit_tool``
|
|
(see Documentation/dev-tools/kunit/run_wrapper.rst).
|
|
|
|
- ``configure`` command generates the kernel ``.config`` from a
|
|
``.kunitconfig`` file (and any architecture-specific options).
|
|
The Python scripts available in ``qemu_configs`` folder
|
|
(for example, ``tools/testing/kunit/qemu configs/powerpc.py``) contains
|
|
additional configuration options for specific architectures.
|
|
It parses both the existing ``.config`` and the ``.kunitconfig`` files
|
|
to ensure that ``.config`` is a superset of ``.kunitconfig``.
|
|
If not, it will combine the two and run ``make olddefconfig`` to regenerate
|
|
the ``.config`` file. It then checks to see if ``.config`` has become a superset.
|
|
This verifies that all the Kconfig dependencies are correctly specified in the
|
|
file ``.kunitconfig``. The ``kunit_config.py`` script contains the code for parsing
|
|
Kconfigs. The code which runs ``make olddefconfig`` is part of the
|
|
``kunit_kernel.py`` script. You can invoke this command through:
|
|
``./tools/testing/kunit/kunit.py config`` and
|
|
generate a ``.config`` file.
|
|
- ``build`` runs ``make`` on the kernel tree with required options
|
|
(depends on the architecture and some options, for example: build_dir)
|
|
and reports any errors.
|
|
To build a KUnit kernel from the current ``.config``, you can use the
|
|
``build`` argument: ``./tools/testing/kunit/kunit.py build``.
|
|
- ``exec`` command executes kernel results either directly (using
|
|
User-mode Linux configuration), or through an emulator such
|
|
as QEMU. It reads results from the log using standard
|
|
output (stdout), and passes them to ``parse`` to be parsed.
|
|
If you already have built a kernel with built-in KUnit tests,
|
|
you can run the kernel and display the test results with the ``exec``
|
|
argument: ``./tools/testing/kunit/kunit.py exec``.
|
|
- ``parse`` extracts the KTAP output from a kernel log, parses
|
|
the test results, and prints a summary. For failed tests, any
|
|
diagnostic output will be included.
|