kunit: Add example for using test->priv

In a test->priv field the user can store arbitrary data.
Add example how to use this feature in the test code.
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: David Gow <davidgow@google.com>
Cc: Rae Moar <rmoar@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

lib/kunit/kunit-example-test.c

@@ -221,6 +221,20 @@ static void example_params_test(struct kunit *test)
 	KUNIT_EXPECT_EQ(test, param->value % param->value, 0);
 }
 
+/*
+ * This test shows the use of test->priv.
+ */
+static void example_priv_test(struct kunit *test)
+{
+	/* unless setup in suite->init(), test->priv is NULL */
+	KUNIT_ASSERT_NULL(test, test->priv);
+
+	/* but can be used to pass arbitrary data to other functions */
+	test->priv = kunit_kzalloc(test, 1, GFP_KERNEL);
+	KUNIT_EXPECT_NOT_NULL(test, test->priv);
+	KUNIT_ASSERT_PTR_EQ(test, test->priv, kunit_get_current_test()->priv);
+}
+
 /*
  * This test should always pass. Can be used to practice filtering attributes.
  */
@@ -245,6 +259,7 @@ static struct kunit_case example_test_cases[] = {
 	KUNIT_CASE(example_mark_skipped_test),
 	KUNIT_CASE(example_all_expect_macros_test),
 	KUNIT_CASE(example_static_stub_test),
+	KUNIT_CASE(example_priv_test),
 	KUNIT_CASE_PARAM(example_params_test, example_gen_params),
 	KUNIT_CASE_SLOW(example_slow_test),
 	{}