[PATCH v3] lib/math: Add int_sqrt test suite

[Luis Felipe Hernandez <luis.hernandez093@gmail.com>]

Adds test suite for integer based square root function.

The test suite is designed to verify the correctness of the int_sqrt()
math library function.

Signed-off-by: Luis Felipe Hernandez <luis.hernandez093@gmail.com>
---
Changes in v2
  - Add new line at the end of int_sqrt_kunit.c
  - Add explicit header includes for MODULE_* macros, strscpy, and ULONG_MAX 

Changes in v3
  - Remove unnecesary new line after Kconfig entry for INT_SQRT_KUNIT_TEST
  - Correct int_sqrt instances with int_sqrt() in commit message and kconfig
entry desc
  - Fix limits.h header include path
---
 lib/Kconfig.debug               | 15 ++++++++++
 lib/math/Makefile               |  1 +
 lib/math/tests/Makefile         |  1 +
 lib/math/tests/int_sqrt_kunit.c | 51 +++++++++++++++++++++++++++++++++
 4 files changed, 68 insertions(+)
 create mode 100644 lib/math/tests/int_sqrt_kunit.c

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 7312ae7c3cc5..c83f5dc9bb48 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2993,6 +2993,21 @@ config TEST_OBJPOOL
 
 	  If unsure, say N.
 
+config INT_SQRT_KUNIT_TEST
+	tristate "Integer square root test test" if !KUNIT_ALL_TESTS
+	depends on KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  This option enables the KUnit test suite for the int_sqrt() function,
+	  which performs square root calculation. The test suite checks
+	  various scenarios, including edge cases, to ensure correctness.
+
+	  Enabling this option will include tests that check various scenarios
+	  and edge cases to ensure the accuracy and reliability of the square root
+	  function.
+
+	  If unsure, say N
+
 endif # RUNTIME_TESTING_MENU
 
 config ARCH_USE_MEMTEST
diff --git a/lib/math/Makefile b/lib/math/Makefile
index 3ef11305f8d2..25bcb968b369 100644
--- a/lib/math/Makefile
+++ b/lib/math/Makefile
@@ -9,3 +9,4 @@ obj-$(CONFIG_INT_POW_TEST)  += tests/int_pow_kunit.o
 obj-$(CONFIG_TEST_DIV64)	+= test_div64.o
 obj-$(CONFIG_TEST_MULDIV64)	+= test_mul_u64_u64_div_u64.o
 obj-$(CONFIG_RATIONAL_KUNIT_TEST) += rational-test.o
+obj-y  += tests/
diff --git a/lib/math/tests/Makefile b/lib/math/tests/Makefile
index 6a169123320a..e1a79f093b2d 100644
--- a/lib/math/tests/Makefile
+++ b/lib/math/tests/Makefile
@@ -1,3 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
 obj-$(CONFIG_INT_POW_TEST) += int_pow_kunit.o
+obj-$(CONFIG_INT_SQRT_KUNIT_TEST) += int_sqrt_kunit.o
diff --git a/lib/math/tests/int_sqrt_kunit.c b/lib/math/tests/int_sqrt_kunit.c
new file mode 100644
index 000000000000..3590142d2012
--- /dev/null
+++ b/lib/math/tests/int_sqrt_kunit.c
@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <kunit/test.h>
+#include <linux/limits.h>
+#include <linux/math.h>
+#include <linux/module.h>
+#include <linux/string.h>
+
+struct test_case_params {
+	unsigned long x;
+	unsigned long expected_result;
+	const char *name;
+};
+
+static const struct test_case_params params[] = {
+	{ 0, 0, "edge-case: square root of 0" },
+	{ 4, 2, "perfect square: square root of 4" },
+	{ 81, 9, "perfect square: square root of 9" },
+	{ 2, 1, "non-perfect square: square root of 2" },
+	{ 5, 2, "non-perfect square: square root of 5"},
+	{ ULONG_MAX, 4294967295, "large input"},
+};
+
+static void get_desc(const struct test_case_params *tc, char *desc)
+{
+	strscpy(desc, tc->name, KUNIT_PARAM_DESC_SIZE);
+}
+
+KUNIT_ARRAY_PARAM(int_sqrt, params, get_desc);
+
+static void int_sqrt_test(struct kunit *test)
+{
+	const struct test_case_params *tc = (const struct test_case_params *)test->param_value;
+
+	KUNIT_EXPECT_EQ(test, tc->expected_result, int_sqrt(tc->x));
+}
+
+static struct kunit_case math_int_sqrt_test_cases[] = {
+	KUNIT_CASE_PARAM(int_sqrt_test, int_sqrt_gen_params),
+	{}
+};
+
+static struct kunit_suite int_sqrt_test_suite = {
+	.name = "math-int_sqrt",
+	.test_cases = math_int_sqrt_test_cases,
+};
+
+kunit_test_suites(&int_sqrt_test_suite);
+
+MODULE_DESCRIPTION("math.int_sqrt KUnit test suite");
+MODULE_LICENSE("GPL");
-- 
2.47.0