[PATCH 1/7] Documentation: kunit: rewrite "Writing Your First Test" section

From: Bagas Sanjaya
Date: Sun Oct 23 2022 - 08:55:29 EST


The "Writing Your First Test" section in "Getting Started"
documentation have wordings that need to be tweaked for clarity and
reducing redundancy. Rewrite the section.

Signed-off-by: Bagas Sanjaya <bagasdotme@xxxxxxxxx>
---
Documentation/dev-tools/kunit/start.rst | 34 +++++++++++++++----------
1 file changed, 21 insertions(+), 13 deletions(-)

diff --git a/Documentation/dev-tools/kunit/start.rst b/Documentation/dev-tools/kunit/start.rst
index f4f504f1fb154f..590e25166efb0d 100644
--- a/Documentation/dev-tools/kunit/start.rst
+++ b/Documentation/dev-tools/kunit/start.rst
@@ -179,15 +179,19 @@ are built-in. Otherwise the module will need to be loaded.

Writing Your First Test
=======================
-In your kernel repository, let's add some code that we can test.
+In this tutorial, you will learn how to write and test a simple driver
+which performs addition of two integers.

-1. Create a file ``drivers/misc/example.h``, which includes:
+1. First, write the driver implementation. Follow the below steps.
+
+ a. Create a new header file ``drivers/misc/example.h`` and add the
+ prototype for ``misc_example_add()``:

.. code-block:: c

int misc_example_add(int left, int right);

-2. Create a file ``drivers/misc/example.c``, which includes:
+ b. Write the function implementation in ``drivers/misc/example.c``:

.. code-block:: c

@@ -200,22 +204,25 @@ In your kernel repository, let's add some code that we can test.
return left + right;
}

-3. Add the following lines to ``drivers/misc/Kconfig``:
+ c. In order for the driver to be selected, add configuration entry to
+ ``drivers/misc/Kconfig``:

.. code-block:: kconfig

config MISC_EXAMPLE
bool "My example"

-4. Add the following lines to ``drivers/misc/Makefile``:
+ d. Last but not least, append the make goal to ``drivers/misc/Makefile``
+ so that the driver can be built:

.. code-block:: make

obj-$(CONFIG_MISC_EXAMPLE) += example.o

-Now we are ready to write the test cases.
+2. Write the test suite that covers the driver functionality. Follow the
+ steps below:

-1. Add the below test case in ``drivers/misc/example_test.c``:
+ a. Write the test in ``drivers/misc/example_test.c``:

.. code-block:: c

@@ -250,7 +257,7 @@ Now we are ready to write the test cases.
};
kunit_test_suite(misc_example_test_suite);

-2. Add the following lines to ``drivers/misc/Kconfig``:
+ b. Add configuration entry for the test suite to ``drivers/misc/Kconfig``:

.. code-block:: kconfig

@@ -259,26 +266,27 @@ Now we are ready to write the test cases.
depends on MISC_EXAMPLE && KUNIT=y
default KUNIT_ALL_TESTS

-3. Add the following lines to ``drivers/misc/Makefile``:
+ c. Append make goal for the configuration to ``drivers/misc/Makefile``:

.. code-block:: make

obj-$(CONFIG_MISC_EXAMPLE_TEST) += example_test.o

-4. Add the following lines to ``.kunit/.kunitconfig``:
+3. In order to enable the driver and its test suite, append configuration
+ fragment to ``.kunit/.kunitconfig``:

.. code-block:: none

CONFIG_MISC_EXAMPLE=y
CONFIG_MISC_EXAMPLE_TEST=y

-5. Run the test:
+4. Run the test:

.. code-block:: bash

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

-You should see the following failure:
+You should see the following output:

.. code-block:: none

@@ -289,7 +297,7 @@ You should see the following failure:
[16:08:57] This test never passes.
...

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

Next Steps
==========
--
An old man doll... just what I always wanted! - Clara