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Subject[PATCH v2 2/7] Documentation: KUnit: Rewrite getting started
From
Clarify the purpose of kunit_tool and fixed consistency issues

Signed-off-by: Harinder Singh <sharinder@google.com>
---
Documentation/dev-tools/kunit/start.rst | 195 +++++++++++++-----------
1 file changed, 102 insertions(+), 93 deletions(-)

diff --git a/Documentation/dev-tools/kunit/start.rst b/Documentation/dev-tools/kunit/start.rst
index 1e00f9226f74..55f8df1abd40 100644
--- a/Documentation/dev-tools/kunit/start.rst
+++ b/Documentation/dev-tools/kunit/start.rst
@@ -4,132 +4,136 @@
Getting Started
===============

-Installing dependencies
+Installing Dependencies
=======================
-KUnit has the same dependencies as the Linux kernel. As long as you can build
-the kernel, you can run KUnit.
+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:
+Running tests with kunit_tool
+=============================
+kunit_tool is a Python script, which configures and builds a kernel, runs
+tests, and formats the test results. From the kernel repository, you
+can run kunit_tool:

.. code-block:: bash

./tools/testing/kunit/kunit.py run

-For more information on this wrapper (also called kunit_tool) check out the
-Documentation/dev-tools/kunit/kunit-tool.rst page.
+For more information on this wrapper, see:
+Documentation/dev-tools/kunit/kunit-tool.rst.
+
+Creating a ``.kunitconfig``
+---------------------------
+
+By default, kunit_tool runs a selection of tests. However, you can specify which
+unit tests to run by creating a ``.kunitconfig`` file with kernel config options
+that enable only a specific set of tests and their dependencies.
+The ``.kunitconfig`` file contains a list of kconfig options which are required
+to run the desired targets. The ``.kunitconfig`` also contains any other test
+specific config options, such as test dependencies. For example: the
+``FAT_FS`` tests - ``FAT_KUNIT_TEST``, depends on
+``FAT_FS``. ``FAT_FS`` can be enabled by selecting either ``MSDOS_FS``
+or ``VFAT_FS``. To run ``FAT_KUNIT_TEST``, the ``.kunitconfig`` has:

-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.
+.. code-block:: none
+
+ CONFIG_KUNIT=y
+ CONFIG_MSDOS_FS=y
+ CONFIG_FAT_KUNIT_TEST=y

-A good starting point for a ``.kunitconfig`` is the KUnit defconfig:
+1. A good starting point for the ``.kunitconfig``, is the KUnit default
+ config. Run the command:

.. code-block:: bash

cd $PATH_TO_LINUX_REPO
cp tools/testing/kunit/configs/default.config .kunitconfig

-You can then add any other Kconfig options you wish, e.g.:
+.. note ::
+ You may want to remove CONFIG_KUNIT_ALL_TESTS from the ``.kunitconfig`` as
+ it will enable a number of additional tests that you may not want.
+
+2. You can then add any other Kconfig options, for example:

.. 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.
+Before running the tests, kunit_tool ensures that all config options
+set in ``.kunitconfig`` are set in the kernel ``.config``. It will warn
+you if you have not included dependencies for the options used.

-.. 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.
+.. note ::
+ The configuration is only updated if the ``.kunitconfig`` is not a
+ subset of ``.config``. You can use tools (for example:
+ 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:
+Running Tests (KUnit Wrapper)
+-----------------------------
+1. To make sure that everything is set up correctly, invoke the Python
+ wrapper from your kernel repository:

.. 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
+.. code-block::

Generating .config ...
Building KUnit Kernel ...
Starting KUnit Kernel ...

-followed by a list of tests that are run. All of them should be passing.
+The tests will pass or fail.

-.. note::
- Because it is building a lot of sources for the first time, the
- ``Building KUnit kernel`` step may take a while.
+.. note ::
+ Because it is building a lot of sources for the first time, the
+ ``Building KUnit kernel`` may take a while.

-Running tests without the KUnit Wrapper
+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
+If you do not want to use the KUnit Wrapper (for example: you want code
+under test to integrate with other systems, or use a different/
+unsupported architecture or configuration), KUnit can be included in
+any kernel, and the results are read out and parsed manually.
+
+.. note ::
+ ``CONFIG_KUNIT`` should not be enabled in a production environment.
+ Enabling KUnit disables Kernel Address-Space Layout Randomization
+ (KASLR), and tests may affect the state of the kernel in ways not
+ suitable for production.
+
+Configuring the Kernel
----------------------
+To enable KUnit itself, you need to enable the ``CONFIG_KUNIT`` Kconfig
+option (under Kernel Hacking/Kernel Testing and Coverage in
+``menuconfig``). From there, you can enable any KUnit tests. They
+usually have config options ending in ``_KUNIT_TEST``.

-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.
+KUnit and KUnit tests can be compiled as modules. The tests in a module
+will run when the module is loaded.

-
-Running the tests (w/o KUnit Wrapper)
+Running Tests (without KUnit Wrapper)
-------------------------------------
+Build and run your kernel. In the kernel log, the test output is printed
+out in the TAP format. This will only happen by default if KUnit/tests
+are built-in. Otherwise the module will need to be loaded.

-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.
-
+.. note ::
+ Some lines and/or data may get interspersed in the TAP output.

-Writing your first test
+Writing Your First Test
=======================
+In your kernel repository, let's add some code that we can test.

-In your kernel repo let's add some code that we can test. Create a file
-``drivers/misc/example.h`` with the contents:
+1. Create a file ``drivers/misc/example.h``, which includes:

.. code-block:: c

int misc_example_add(int left, int right);

-create a file ``drivers/misc/example.c``:
+2. Create a file ``drivers/misc/example.c``, which includes:

.. code-block:: c

@@ -142,21 +146,22 @@ create a file ``drivers/misc/example.c``:
return left + right;
}

-Now add the following lines to ``drivers/misc/Kconfig``:
+3. 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``:
+4. Add 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``:
+Now we are ready to write the test cases.
+
+1. Add the below test case in ``drivers/misc/example_test.c``:

.. code-block:: c

@@ -191,7 +196,7 @@ Now we are ready to write the test. The test will be in
};
kunit_test_suite(misc_example_test_suite);

-Now add the following to ``drivers/misc/Kconfig``:
+2. Add the following lines to ``drivers/misc/Kconfig``:

.. code-block:: kconfig

@@ -200,20 +205,20 @@ Now add the following to ``drivers/misc/Kconfig``:
depends on MISC_EXAMPLE && KUNIT=y
default KUNIT_ALL_TESTS

-and the following to ``drivers/misc/Makefile``:
+3. Add the following lines to ``drivers/misc/Makefile``:

.. code-block:: make

- obj-$(CONFIG_MISC_EXAMPLE_TEST) += example-test.o
+ obj-$(CONFIG_MISC_EXAMPLE_TEST) += example_test.o

-Now add it to your ``.kunitconfig``:
+4. Add the following lines to ``.kunitconfig``:

.. code-block:: none

CONFIG_MISC_EXAMPLE=y
CONFIG_MISC_EXAMPLE_TEST=y

-Now you can run the test:
+5. Run the test:

.. code-block:: bash

@@ -227,16 +232,20 @@ You should see the following failure:
[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.
+ [16:08:57] This test never passes.
...

-Congrats! You just wrote your first KUnit test!
+Congrats! You just wrote your first KUnit test.

Next Steps
==========
-* Check out the Documentation/dev-tools/kunit/tips.rst page for tips on
- writing idiomatic KUnit tests.
-* Check out the :doc:`running_tips` page for tips on
- how to make running KUnit tests easier.
-* Optional: see the :doc:`usage` page for a more
- in-depth explanation of KUnit.
+
+* Documentation/dev-tools/kunit/usage.rst - KUnit features.
+* Documentation/dev-tools/kunit/tips.rst - best practices with
+ examples.
+* Documentation/dev-tools/kunit/api/index.rst - KUnit APIs
+ used for testing.
+* Documentation/dev-tools/kunit/kunit-tool.rst - kunit_tool helper
+ script.
+* Documentation/dev-tools/kunit/faq.rst - KUnit common questions and
+ answers.
--
2.34.1.400.ga245620fadb-goog
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