Add example_params_test_with_init() to illustrate how to manage
shared resources across a parameterized KUnit test. This example
showcases the use of the new param_init() function and its registration
to a test using the KUNIT_CASE_PARAM_WITH_INIT() macro.

Additionally, the test demonstrates how to directly pass a parameter array
to the parameterized test context via kunit_register_params_array()
and leveraging the Resource API for shared resource management.

Signed-off-by: Marie Zhussupova <marie...@google.com>
---

Changes in v2:

- kunit_array_gen_params() is now explicitly passed to
  KUNIT_CASE_PARAM_WITH_INIT() to be consistent with
  a parameterized test being defined by the existence
  of the generate_params() function.
- The comments were edited to be more concise.
- The patch header was changed to reflect that this example
  test's intent is more aligned with showcasing using the
  Resource API for shared resource management.
- The comments and the commit message were changed to
  reflect the parameterized testing terminology. See
  the patch series cover letter change log for the
  definitions.

---

 lib/kunit/kunit-example-test.c | 118 +++++++++++++++++++++++++++++++++
 1 file changed, 118 insertions(+)

diff --git a/lib/kunit/kunit-example-test.c b/lib/kunit/kunit-example-test.c
index 3056d6bc705d..f2819ee58965 100644
--- a/lib/kunit/kunit-example-test.c
+++ b/lib/kunit/kunit-example-test.c
@@ -277,6 +277,122 @@ static void example_slow_test(struct kunit *test)
        KUNIT_EXPECT_EQ(test, 1 + 1, 2);
 }
 
+/*
+ * This custom function allocates memory and sets the information we want
+ * stored in the kunit_resource->data field.
+ */
+static int example_resource_init(struct kunit_resource *res, void *context)
+{
+       int *info = kmalloc(sizeof(*info), GFP_KERNEL);
+
+       if (!info)
+               return -ENOMEM;
+       *info = *(int *)context;
+       res->data = info;
+       return 0;
+}
+
+/*
+ * This function deallocates memory for the kunit_resource->data field.
+ */
+static void example_resource_free(struct kunit_resource *res)
+{
+       kfree(res->data);
+}
+
+/*
+ * This match function is invoked by kunit_find_resource() to locate
+ * a test resource based on certain criteria.
+ */
+static bool example_resource_alloc_match(struct kunit *test,
+                                        struct kunit_resource *res,
+                                        void *match_data)
+{
+       return res->data && res->free == example_resource_free;
+}
+
+/*
+ * This is an example of a function that provides a description for each of the
+ * parameters in a parameterized test.
+ */
+static void example_param_array_get_desc(struct kunit *test, const void *p, 
char *desc)
+{
+       const struct example_param *param = p;
+
+       snprintf(desc, KUNIT_PARAM_DESC_SIZE,
+                "example check if %d is less than or equal to 3", 
param->value);
+}
+
+/*
+ * This function gets passed in the parameterized test context i.e. the
+ * struct kunit belonging to the parameterized test. You can use this function
+ * to add resources you want shared across the whole parameterized test or
+ * for additional setup.
+ */
+static int example_param_init(struct kunit *test)
+{
+       int ctx = 3; /* Data to be stored. */
+       size_t arr_size = ARRAY_SIZE(example_params_array);
+
+       /*
+        * This allocates a struct kunit_resource, sets its data field to
+        * ctx, and adds it to the struct kunit's resources list. Note that
+        * this is parameterized test managed. So, it doesn't need to have
+        * a custom exit function to deallocation as it will get cleaned up at
+        * the end of the parameterized test.
+        */
+       void *data = kunit_alloc_resource(test, example_resource_init, 
example_resource_free,
+                                         GFP_KERNEL, &ctx);
+
+       if (!data)
+               return -ENOMEM;
+       /*
+        * Pass the parameter array information to the parameterized test 
context
+        * struct kunit. Note that you will need to provide 
kunit_array_gen_params()
+        * as the generator function to KUNIT_CASE_PARAM_WITH_INIT() when 
registering
+        * a parameter array this route.
+        *
+        * Alternatively, since this is a static array we can also use
+        * KUNIT_CASE_PARAM_ARRAY(,DESC) to create  a `*_gen_params()` function
+        * and pass that to  KUNIT_CASE_PARAM_WITH_INIT() instead of registering
+        * the parameter array here.
+        */
+       kunit_register_params_array(test, example_params_array, arr_size,
+                                   example_param_array_get_desc);
+       return 0;
+}
+
+/*
+ * This is an example of a test that uses shared resources available in the
+ * parameterized test context.
+ */
+static void example_params_test_with_init(struct kunit *test)
+{
+       int threshold;
+       struct kunit_resource *res;
+       const struct example_param *param = test->param_value;
+
+       /* By design, param pointer will not be NULL. */
+       KUNIT_ASSERT_NOT_NULL(test, param);
+
+       /*
+        * Here we pass test->parent to search for shared resources in the
+        * parameterized test context.
+        */
+       res = kunit_find_resource(test->parent, example_resource_alloc_match, 
NULL);
+
+       KUNIT_ASSERT_NOT_NULL(test, res);
+
+       /* Since kunit_resource->data is a void pointer we need to typecast it. 
*/
+       threshold = *((int *)res->data);
+
+       /* Assert that the parameter is less than or equal to a certain 
threshold. */
+       KUNIT_ASSERT_LE(test, param->value, threshold);
+
+       /* This decreases the reference count after calling 
kunit_find_resource(). */
+       kunit_put_resource(res);
+}
+
 /*
  * Here we make a list of all the test cases we want to add to the test suite
  * below.
@@ -296,6 +412,8 @@ static struct kunit_case example_test_cases[] = {
        KUNIT_CASE(example_static_stub_using_fn_ptr_test),
        KUNIT_CASE(example_priv_test),
        KUNIT_CASE_PARAM(example_params_test, example_gen_params),
+       KUNIT_CASE_PARAM_WITH_INIT(example_params_test_with_init, 
kunit_array_gen_params,
+                                  example_param_init, NULL),
        KUNIT_CASE_SLOW(example_slow_test),
        {}
 };
-- 
2.51.0.rc0.205.g4a044479a3-goog

Reply via email to