scanf: break kunit into test cases

Use `suite_init` and move some tests into `scanf_test_cases`. This
gives us nicer output in the event of a failure.

Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20250307-scanf-kunit-convert-v9-4-b98820fa39ff@gmail.com
Signed-off-by: Kees Cook <kees@kernel.org>

Author: tamird

lib/tests/scanf_kunit.c

@@ -434,8 +434,11 @@ static void numbers_list_hh(struct kunit *test, const char *delim)
 	numbers_list_8(signed char,	   "0x%hhx", delim, "hhi", check_char);
 }
 
-static void numbers_list(struct kunit *test, const char *delim)
+static void numbers_list(struct kunit *test)
 {
+	const char * const *param = test->param_value;
+	const char *delim = *param;
+
 	numbers_list_ll(test, delim);
 	numbers_list_l(test, delim);
 	numbers_list_d(test, delim);
@@ -506,8 +509,11 @@ static void numbers_list_field_width_hh(struct kunit *test, const char *delim)
  * List of numbers separated by delim. Each field width specifier is the
  * maximum possible digits for the given type and base.
  */
-static void numbers_list_field_width_typemax(struct kunit *test, const char *delim)
+static void numbers_list_field_width_typemax(struct kunit *test)
 {
+	const char * const *param = test->param_value;
+	const char *delim = *param;
+
 	numbers_list_field_width_ll(test, delim);
 	numbers_list_field_width_l(test, delim);
 	numbers_list_field_width_d(test, delim);
@@ -569,8 +575,11 @@ static void numbers_list_field_width_val_hh(struct kunit *test, const char *deli
  * List of numbers separated by delim. Each field width specifier is the
  * exact length of the corresponding value digits in the string being scanned.
  */
-static void numbers_list_field_width_val_width(struct kunit *test, const char *delim)
+static void numbers_list_field_width_val_width(struct kunit *test)
 {
+	const char * const *param = test->param_value;
+	const char *delim = *param;
+
 	numbers_list_field_width_val_ll(test, delim);
 	numbers_list_field_width_val_l(test, delim);
 	numbers_list_field_width_val_d(test, delim);
@@ -586,7 +595,12 @@ static void numbers_list_field_width_val_width(struct kunit *test, const char *d
  */
 static void numbers_slice(struct kunit *test)
 {
-	numbers_list_field_width_val_width(test, "");
+	const char *delim = "";
+
+	KUNIT_ASSERT_PTR_EQ(test, test->param_value, NULL);
+	test->param_value = &delim;
+
+	numbers_list_field_width_val_width(test);
 }
 
 #define test_number_prefix(T, str, scan_fmt, expect0, expect1, n_args, fn)	\
@@ -737,62 +751,60 @@ static const char * const number_delimiters[] = {
 	" ", ":", ",", "-", "/",
 };
 
-static void test_numbers(struct kunit *test)
+static void number_delimiter_param_desc(const char * const *param,
+					   char *desc)
 {
-	int i;
+	snprintf(desc, KUNIT_PARAM_DESC_SIZE, "\"%s\"", *param);
+}
 
-	/* String containing only one number. */
-	numbers_simple(test);
+KUNIT_ARRAY_PARAM(number_delimiters, number_delimiters, number_delimiter_param_desc);
 
+static struct kunit_case scanf_test_cases[] = {
+	KUNIT_CASE(numbers_simple),
 	/* String with multiple numbers separated by delimiter. */
-	for (i = 0; i < ARRAY_SIZE(number_delimiters); i++) {
-		numbers_list(test, number_delimiters[i]);
-
-		/* Field width may be longer than actual field digits. */
-		numbers_list_field_width_typemax(test, number_delimiters[i]);
-
-		/* Each field width exactly length of actual field digits. */
-		numbers_list_field_width_val_width(test, number_delimiters[i]);
-	}
-
+	KUNIT_CASE_PARAM(numbers_list, number_delimiters_gen_params),
+	/* Field width may be longer than actual field digits. */
+	KUNIT_CASE_PARAM(numbers_list_field_width_typemax, number_delimiters_gen_params),
+	/* Each field width exactly length of actual field digits. */
+	KUNIT_CASE_PARAM(numbers_list_field_width_val_width, number_delimiters_gen_params),
 	/* Slice continuous sequence of digits using field widths. */
-	numbers_slice(test);
+	KUNIT_CASE(numbers_slice),
+	KUNIT_CASE(numbers_prefix_overflow),
 
-	numbers_prefix_overflow(test);
-}
+	KUNIT_CASE(test_simple_strtoull),
+	KUNIT_CASE(test_simple_strtoll),
+	KUNIT_CASE(test_simple_strtoul),
+	KUNIT_CASE(test_simple_strtol),
+	{}
+};
 
-static void scanf_test(struct kunit *test)
+static int scanf_suite_init(struct kunit_suite *suite)
 {
 	test_buffer = kmalloc(BUF_SIZE, GFP_KERNEL);
 	if (!test_buffer)
-		return;
+		return -ENOMEM;
 
 	fmt_buffer = kmalloc(BUF_SIZE, GFP_KERNEL);
 	if (!fmt_buffer) {
 		kfree(test_buffer);
-		return;
+		return -ENOMEM;
 	}
 
 	prandom_seed_state(&rnd_state, 3141592653589793238ULL);
 
-	test_numbers(test);
-
-	test_simple_strtoull(test);
-	test_simple_strtoll(test);
-	test_simple_strtoul(test);
-	test_simple_strtol(test);
+	return 0;
+}
 
+static void scanf_suite_exit(struct kunit_suite *suite)
+{
 	kfree(fmt_buffer);
 	kfree(test_buffer);
 }
 
-static struct kunit_case scanf_test_cases[] = {
-	KUNIT_CASE(scanf_test),
-	{}
-};
-
 static struct kunit_suite scanf_test_suite = {
 	.name = "scanf",
+	.suite_init = scanf_suite_init,
+	.suite_exit = scanf_suite_exit,
 	.test_cases = scanf_test_cases,
 };