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Diffstat (limited to '')
-rw-r--r-- | Documentation/dev-tools/kunit/usage.rst | 81 |
1 files changed, 71 insertions, 10 deletions
diff --git a/Documentation/dev-tools/kunit/usage.rst b/Documentation/dev-tools/kunit/usage.rst index 9db12e9166..22955d56b3 100644 --- a/Documentation/dev-tools/kunit/usage.rst +++ b/Documentation/dev-tools/kunit/usage.rst @@ -566,13 +566,9 @@ By reusing the same ``cases`` array from above, we can write the test as a }, }; - // Need a helper function to generate a name for each test case. - static void case_to_desc(const struct sha1_test_case *t, char *desc) - { - strcpy(desc, t->str); - } - // Creates `sha1_gen_params()` to iterate over `cases`. - KUNIT_ARRAY_PARAM(sha1, cases, case_to_desc); + // Creates `sha1_gen_params()` to iterate over `cases` while using + // the struct member `str` for the case description. + KUNIT_ARRAY_PARAM_DESC(sha1, cases, str); // Looks no different from a normal test. static void sha1_test(struct kunit *test) @@ -588,7 +584,7 @@ By reusing the same ``cases`` array from above, we can write the test as a } // Instead of KUNIT_CASE, we use KUNIT_CASE_PARAM and pass in the - // function declared by KUNIT_ARRAY_PARAM. + // function declared by KUNIT_ARRAY_PARAM or KUNIT_ARRAY_PARAM_DESC. static struct kunit_case sha1_test_cases[] = { KUNIT_CASE_PARAM(sha1_test, sha1_gen_params), {} @@ -675,8 +671,23 @@ Testing Static Functions ------------------------ If we do not want to expose functions or variables for testing, one option is to -conditionally ``#include`` the test file at the end of your .c file. For -example: +conditionally export the used symbol. For example: + +.. code-block:: c + + /* In my_file.c */ + + VISIBLE_IF_KUNIT int do_interesting_thing(); + EXPORT_SYMBOL_IF_KUNIT(do_interesting_thing); + + /* In my_file.h */ + + #if IS_ENABLED(CONFIG_KUNIT) + int do_interesting_thing(void); + #endif + +Alternatively, you could conditionally ``#include`` the test file at the end of +your .c file. For example: .. code-block:: c @@ -797,3 +808,53 @@ structures as shown below: KUnit is not enabled, or if no test is running in the current task, it will do nothing. This compiles down to either a no-op or a static key check, so will have a negligible performance impact when no test is running. + +Managing Fake Devices and Drivers +--------------------------------- + +When testing drivers or code which interacts with drivers, many functions will +require a ``struct device`` or ``struct device_driver``. In many cases, setting +up a real device is not required to test any given function, so a fake device +can be used instead. + +KUnit provides helper functions to create and manage these fake devices, which +are internally of type ``struct kunit_device``, and are attached to a special +``kunit_bus``. These devices support managed device resources (devres), as +described in Documentation/driver-api/driver-model/devres.rst + +To create a KUnit-managed ``struct device_driver``, use ``kunit_driver_create()``, +which will create a driver with the given name, on the ``kunit_bus``. This driver +will automatically be destroyed when the corresponding test finishes, but can also +be manually destroyed with ``driver_unregister()``. + +To create a fake device, use the ``kunit_device_register()``, which will create +and register a device, using a new KUnit-managed driver created with ``kunit_driver_create()``. +To provide a specific, non-KUnit-managed driver, use ``kunit_device_register_with_driver()`` +instead. Like with managed drivers, KUnit-managed fake devices are automatically +cleaned up when the test finishes, but can be manually cleaned up early with +``kunit_device_unregister()``. + +The KUnit devices should be used in preference to ``root_device_register()``, and +instead of ``platform_device_register()`` in cases where the device is not otherwise +a platform device. + +For example: + +.. code-block:: c + + #include <kunit/device.h> + + static void test_my_device(struct kunit *test) + { + struct device *fake_device; + const char *dev_managed_string; + + // Create a fake device. + fake_device = kunit_device_register(test, "my_device"); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, fake_device) + + // Pass it to functions which need a device. + dev_managed_string = devm_kstrdup(fake_device, "Hello, World!"); + + // Everything is cleaned up automatically when the test ends. + }
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