[PATCH 1/2] kunit: Add param generator macro for zero terminated arrays

[Michal Wajdeczko <michal.wajdeczko@intel.com>]

The existing macro KUNIT_ARRAY_PARAM can produce parameter
generator function but only when we fully know the definition
of the array. However, there might be cases where we would like
to generate test params based on externaly defined array, which
is defined as zero-terminated array, like pci_driver.id_table.

Add helper macro KUNIT_ZERO_ARRAY_PARAM that can work with zero
terminated arrays and provide example how to use it.

$ ./tools/testing/kunit/kunit.py run \
	--kunitconfig ./lib/kunit/.kunitconfig *.example_params*

[ ] Starting KUnit Kernel (1/1)...
[ ] ============================================================
[ ] ========================= example  =========================
[ ] =================== example_params_test  ===================
[ ] [SKIPPED] example value 3
[ ] [PASSED] example value 2
[ ] [PASSED] example value 1
[ ] [SKIPPED] example value 0
[ ] =============== [PASSED] example_params_test ===============
[ ] =================== example_params_test  ===================
[ ] [SKIPPED] example value 3
[ ] [PASSED] example value 2
[ ] [PASSED] example value 1
[ ] =============== [PASSED] example_params_test ===============
[ ] ===================== [PASSED] example =====================
[ ] ============================================================
[ ] Testing complete. Ran 7 tests: passed: 4, skipped: 3

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: David Gow <davidgow@google.com>
Cc: Rae Moar <rmoar@google.com>
---
 include/kunit/test.h           | 22 ++++++++++++++++++++++
 lib/kunit/kunit-example-test.c |  2 ++
 2 files changed, 24 insertions(+)

diff --git a/include/kunit/test.h b/include/kunit/test.h
index 20ed9f9275c9..280113ceb6a6 100644
--- a/include/kunit/test.h
+++ b/include/kunit/test.h
@@ -1514,6 +1514,28 @@ do {									       \
 		return NULL;									\
 	}
 
+/**
+ * KUNIT_ZERO_ARRAY_PARAM() - Define test parameter generator from a zero terminated array.
+ * @name:  prefix for the test parameter generator function.
+ * @array: zero terminated array of test parameters.
+ * @get_desc: function to convert param to description; NULL to use default
+ *
+ * Define function @name_gen_params which uses zero terminated @array to generate parameters.
+ */
+#define KUNIT_ZERO_ARRAY_PARAM(name, array, get_desc)						\
+	static const void *name##_gen_params(const void *prev, char *desc)			\
+	{											\
+		typeof((array)[0]) *__prev = prev;						\
+		typeof(__prev) __next = __prev ? __prev + 1 : (array);				\
+		void (*__get_desc)(typeof(__next), char *) = get_desc;				\
+		for (; memchr_inv(__next, 0, sizeof(*__next)); __prev = __next++) {		\
+			if (__get_desc)								\
+				__get_desc(__next, desc);					\
+			return __next;								\
+		}										\
+		return NULL;									\
+	}
+
 // TODO(dlatypov@google.com): consider eventually migrating users to explicitly
 // include resource.h themselves if they need it.
 #include <kunit/resource.h>
diff --git a/lib/kunit/kunit-example-test.c b/lib/kunit/kunit-example-test.c
index 6bb5c2ef6696..ad9ebcfd513e 100644
--- a/lib/kunit/kunit-example-test.c
+++ b/lib/kunit/kunit-example-test.c
@@ -202,6 +202,7 @@ static void example_param_get_desc(const struct example_param *p, char *desc)
 }
 
 KUNIT_ARRAY_PARAM(example, example_params_array, example_param_get_desc);
+KUNIT_ZERO_ARRAY_PARAM(example_zero, example_params_array, example_param_get_desc);
 
 /*
  * This test shows the use of params.
@@ -246,6 +247,7 @@ static struct kunit_case example_test_cases[] = {
 	KUNIT_CASE(example_all_expect_macros_test),
 	KUNIT_CASE(example_static_stub_test),
 	KUNIT_CASE_PARAM(example_params_test, example_gen_params),
+	KUNIT_CASE_PARAM(example_params_test, example_zero_gen_params),
 	KUNIT_CASE_SLOW(example_slow_test),
 	{}
 };
-- 
2.25.1