kunit: add ability to specify suite-level init and exit functions

KUnit has support for setup/cleanup logic for each test case in a suite.
But it lacks the ability to specify setup/cleanup for the entire suite
itself.

This can be used to do setup that is too expensive or cumbersome to do
for each test.
Or it can be used to do simpler things like log debug information after
the suite completes.
It's a fairly common feature, so the lack of it is noticeable.

Some examples in other frameworks and languages:
* https://docs.python.org/3/library/unittest.html#setupclass-and-teardownclass
* https://google.github.io/googletest/reference/testing.html#Test::SetUpTestSuite

Meta:
This is very similar to this patch here: https://lore.kernel.org/linux-kselftest/20210805043503.20252-3-bvanassche@acm.org/
The changes from that patch:
* pass in `struct kunit *` so users can do stuff like
  `kunit_info(suite, "debug message")`
* makes sure the init failure is bubbled up as a failure
* updates kunit-example-test.c to use a suite init
* Updates kunit/usage.rst to mention the new support
* some minor cosmetic things
  * use `suite_{init,exit}` instead of `{init/exit}_suite`
  * make suite init error message more consistent w/ test init
  * etc.

Signed-off-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

1 files changed, 11 insertions, 8 deletions

diff --git a/Documentation/dev-tools/kunit/usage.rst b/Documentation/dev-tools/kunit/usage.rst
index 1c83e7d60a8a..d62a04255c2e 100644
--- a/Documentation/dev-tools/kunit/usage.rst
+++ b/Documentation/dev-tools/kunit/usage.rst
@@ -125,8 +125,8 @@ We need many test cases covering all the unit's behaviors. It is common to have
 many similar tests. In order to reduce duplication in these closely related
 tests, most unit testing frameworks (including KUnit) provide the concept of a
 *test suite*. A test suite is a collection of test cases for a unit of code
-with a setup function that gets invoked before every test case and then a tear
-down function that gets invoked after every test case completes. For example:
+with optional setup and teardown functions that run before/after the whole
+suite and/or every test case. For example:
 
 .. code-block:: c
 
@@ -141,16 +141,19 @@ down function that gets invoked after every test case completes. For example:
 		.name = "example",
 		.init = example_test_init,
 		.exit = example_test_exit,
+		.suite_init = example_suite_init,
+		.suite_exit = example_suite_exit,
 		.test_cases = example_test_cases,
 	};
 	kunit_test_suite(example_test_suite);
 
-In the above example, the test suite ``example_test_suite`` would run the test
-cases ``example_test_foo``, ``example_test_bar``, and ``example_test_baz``. Each
-would have ``example_test_init`` called immediately before it and
-``example_test_exit`` called immediately after it.
-``kunit_test_suite(example_test_suite)`` registers the test suite with the
-KUnit test framework.
+In the above example, the test suite ``example_test_suite`` would first run
+``example_suite_init``, then run the test cases ``example_test_foo``,
+``example_test_bar``, and ``example_test_baz``. Each would have
+``example_test_init`` called immediately before it and ``example_test_exit``
+called immediately after it. Finally, ``example_suite_exit`` would be called
+after everything else. ``kunit_test_suite(example_test_suite)`` registers the
+test suite with the KUnit test framework.
 
 .. note::
    A test case will only run if it is associated with a test suite.