[PATCH 4/6] lib: Add basic KUnit test for lib/math

Devarsh Thakkar
2024-07-08T16:00:14Z

From: Daniel Latypov <dlatypov@google.com>

Add basic test coverage for files that don't require any config options:
* part of math.h (what seem to be the most commonly used macros)
* gcd.c
* lcm.c
* int_sqrt.c
* reciprocal_div.c
(Ignored int_pow.c since it's a simple textbook algorithm.)

These tests aren't particularly interesting, but they
* provide short and simple examples of parameterized tests
* provide a place to add tests for any new files in this dir
* are written so adding new test cases to cover edge cases should be
easy
* looking at code coverage, we hit all the branches in the .c files

Signed-off-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
[devarsht: Rebase to 6.9, remove kernel.h, update Kconfig and change license to GPL]
Signed-off-by: Devarsh Thakkar <devarsht@ti.com>
---
lib/math/Kconfig | 14 ++
lib/math/Makefile | 1 +
lib/math/math_kunit.c | 294 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 309 insertions(+)
create mode 100644 lib/math/math_kunit.c

diff --git a/lib/math/Kconfig b/lib/math/Kconfig
index 0634b428d0cb..f738d8a433ea 100644
--- a/lib/math/Kconfig
+++ b/lib/math/Kconfig
@@ -15,3 +15,17 @@ config PRIME_NUMBERS

config RATIONAL
tristate
+
+config MATH_KUNIT_TEST
+ tristate "KUnit test for math helper functions"
+ depends on KUNIT
+ default KUNIT_ALL_TESTS
+
+ help
+ This builds unit test for math helper functions as defined in lib/math
+ and math.h.
+
+ For more information on KUNIT and unit tests in general, please refer
+ to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+ If unsure, say N.
diff --git a/lib/math/Makefile b/lib/math/Makefile
index 91fcdb0c9efe..dcf65d10dab2 100644
--- a/lib/math/Makefile
+++ b/lib/math/Makefile
@@ -7,3 +7,4 @@ obj-$(CONFIG_RATIONAL) += rational.o

obj-$(CONFIG_TEST_DIV64) += test_div64.o
obj-$(CONFIG_RATIONAL_KUNIT_TEST) += rational-test.o
+obj-$(CONFIG_MATH_KUNIT_TEST) += math_kunit.o
diff --git a/lib/math/math_kunit.c b/lib/math/math_kunit.c
new file mode 100644
index 000000000000..be27f2afb8e4
--- /dev/null
+++ b/lib/math/math_kunit.c
@@ -0,0 +1,294 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Simple KUnit suite for math helper funcs that are always enabled.
+ *
+ * Copyright (C) 2020, Google LLC.
+ * Author: Daniel Latypov <dlatypov@google.com>
+ */
+
+#include <kunit/test.h>
+#include <linux/gcd.h>
+#include <linux/lcm.h>
+#include <linux/math.h>
+#include <linux/module.h>
+#include <linux/reciprocal_div.h>
+#include <linux/types.h>
+
+static void abs_test(struct kunit *test)
+{
+ KUNIT_EXPECT_EQ(test, abs((char)0), (char)0);
+ KUNIT_EXPECT_EQ(test, abs((char)42), (char)42);
+ KUNIT_EXPECT_EQ(test, abs((char)-42), (char)42);
+
+ /* The expression in the macro is actually promoted to an int. */
+ KUNIT_EXPECT_EQ(test, abs((short)0), 0);
+ KUNIT_EXPECT_EQ(test, abs((short)42), 42);
+ KUNIT_EXPECT_EQ(test, abs((short)-42), 42);
+
+ KUNIT_EXPECT_EQ(test, abs(0), 0);
+ KUNIT_EXPECT_EQ(test, abs(42), 42);
+ KUNIT_EXPECT_EQ(test, abs(-42), 42);
+
+ KUNIT_EXPECT_EQ(test, abs(0L), 0L);
+ KUNIT_EXPECT_EQ(test, abs(42L), 42L);
+ KUNIT_EXPECT_EQ(test, abs(-42L), 42L);
+
+ KUNIT_EXPECT_EQ(test, abs(0LL), 0LL);
+ KUNIT_EXPECT_EQ(test, abs(42LL), 42LL);
+ KUNIT_EXPECT_EQ(test, abs(-42LL), 42LL);
+
+ /* Unsigned types get casted to signed. */
+ KUNIT_EXPECT_EQ(test, abs(0ULL), 0LL);
+ KUNIT_EXPECT_EQ(test, abs(42ULL), 42LL);
+}
+
+static void int_sqrt_test(struct kunit *test)
+{
+ KUNIT_EXPECT_EQ(test, int_sqrt(0UL), 0UL);
+ KUNIT_EXPECT_EQ(test, int_sqrt(1UL), 1UL);
+ KUNIT_EXPECT_EQ(test, int_sqrt(4UL), 2UL);
+ KUNIT_EXPECT_EQ(test, int_sqrt(5UL), 2UL);
+ KUNIT_EXPECT_EQ(test, int_sqrt(8UL), 2UL);
+ KUNIT_EXPECT_EQ(test, int_sqrt(1UL << 30), 1UL << 15);
+}
+
+static void round_up_test(struct kunit *test)
+{
+ KUNIT_EXPECT_EQ(test, round_up(0, 1), 0);
+ KUNIT_EXPECT_EQ(test, round_up(1, 2), 2);
+ KUNIT_EXPECT_EQ(test, round_up(3, 2), 4);
+ KUNIT_EXPECT_EQ(test, round_up((1 << 30) - 1, 2), 1 << 30);
+ KUNIT_EXPECT_EQ(test, round_up((1 << 30) - 1, 1 << 29), 1 << 30);
+}
+
+static void round_down_test(struct kunit *test)
+{
+ KUNIT_EXPECT_EQ(test, round_down(0, 1), 0);
+ KUNIT_EXPECT_EQ(test, round_down(1, 2), 0);
+ KUNIT_EXPECT_EQ(test, round_down(3, 2), 2);
+ KUNIT_EXPECT_EQ(test, round_down((1 << 30) - 1, 2), (1 << 30) - 2);
+ KUNIT_EXPECT_EQ(test, round_down((1 << 30) - 1, 1 << 29), 1 << 29);
+}
+
+/* These versions can round to numbers that aren't a power of two */
+static void roundup_test(struct kunit *test)
+{
+ KUNIT_EXPECT_EQ(test, roundup(0, 1), 0);
+ KUNIT_EXPECT_EQ(test, roundup(1, 2), 2);
+ KUNIT_EXPECT_EQ(test, roundup(3, 2), 4);
+ KUNIT_EXPECT_EQ(test, roundup((1 << 30) - 1, 2), 1 << 30);
+ KUNIT_EXPECT_EQ(test, roundup((1 << 30) - 1, 1 << 29), 1 << 30);
+
+ KUNIT_EXPECT_EQ(test, roundup(3, 2), 4);
+ KUNIT_EXPECT_EQ(test, roundup(4, 3), 6);
+}
+
+static void rounddown_test(struct kunit *test)
+{
+ KUNIT_EXPECT_EQ(test, rounddown(0, 1), 0);
+ KUNIT_EXPECT_EQ(test, rounddown(1, 2), 0);
+ KUNIT_EXPECT_EQ(test, rounddown(3, 2), 2);
+ KUNIT_EXPECT_EQ(test, rounddown((1 << 30) - 1, 2), (1 << 30) - 2);
+ KUNIT_EXPECT_EQ(test, rounddown((1 << 30) - 1, 1 << 29), 1 << 29);
+
+ KUNIT_EXPECT_EQ(test, rounddown(3, 2), 2);
+ KUNIT_EXPECT_EQ(test, rounddown(4, 3), 3);
+}
+
+static void div_round_up_test(struct kunit *test)
+{
+ KUNIT_EXPECT_EQ(test, DIV_ROUND_UP(0, 1), 0);
+ KUNIT_EXPECT_EQ(test, DIV_ROUND_UP(20, 10), 2);
+ KUNIT_EXPECT_EQ(test, DIV_ROUND_UP(21, 10), 3);
+ KUNIT_EXPECT_EQ(test, DIV_ROUND_UP(21, 20), 2);
+ KUNIT_EXPECT_EQ(test, DIV_ROUND_UP(21, 99), 1);
+}
+
+static void div_round_closest_test(struct kunit *test)
+{
+ KUNIT_EXPECT_EQ(test, DIV_ROUND_CLOSEST(0, 1), 0);
+ KUNIT_EXPECT_EQ(test, DIV_ROUND_CLOSEST(20, 10), 2);
+ KUNIT_EXPECT_EQ(test, DIV_ROUND_CLOSEST(21, 10), 2);
+ KUNIT_EXPECT_EQ(test, DIV_ROUND_CLOSEST(25, 10), 3);
+}
+
+/* Generic test case for unsigned long inputs. */
+struct test_case {
+ unsigned long a, b;
+ unsigned long result;
+};
+
+static struct test_case gcd_cases[] = {
+ {
+ .a = 0, .b = 0,
+ .result = 0,
+ },
+ {
+ .a = 0, .b = 1,
+ .result = 1,
+ },
+ {
+ .a = 2, .b = 2,
+ .result = 2,
+ },
+ {
+ .a = 2, .b = 4,
+ .result = 2,
+ },
+ {
+ .a = 3, .b = 5,
+ .result = 1,
+ },
+ {
+ .a = 3 * 9, .b = 3 * 5,
+ .result = 3,
+ },
+ {
+ .a = 3 * 5 * 7, .b = 3 * 5 * 11,
+ .result = 15,
+ },
+ {
+ .a = 1 << 21,
+ .b = (1 << 21) - 1,
+ .result = 1,
+ },
+};
+
+KUNIT_ARRAY_PARAM(gcd, gcd_cases, NULL);
+
+static void gcd_test(struct kunit *test)
+{
+ const char *message_fmt = "gcd(%lu, %lu)";
+ const struct test_case *test_param = test->param_value;
+
+ KUNIT_EXPECT_EQ_MSG(test, test_param->result,
+ gcd(test_param->a, test_param->b),
+ message_fmt, test_param->a,
+ test_param->b);
+
+ if (test_param->a == test_param->b)
+ return;
+
+ /* gcd(a,b) == gcd(b,a) */
+ KUNIT_EXPECT_EQ_MSG(test, test_param->result,
+ gcd(test_param->b, test_param->a),
+ message_fmt, test_param->b,
+ test_param->a);
+}
+
+static struct test_case lcm_cases[] = {
+ {
+ .a = 0, .b = 0,
+ .result = 0,
+ },
+ {
+ .a = 0, .b = 1,
+ .result = 0,
+ },
+ {
+ .a = 1, .b = 2,
+ .result = 2,
+ },
+ {
+ .a = 2, .b = 2,
+ .result = 2,
+ },
+ {
+ .a = 3 * 5, .b = 3 * 7,
+ .result = 3 * 5 * 7,
+ },
+};
+
+KUNIT_ARRAY_PARAM(lcm, lcm_cases, NULL);
+
+static void lcm_test(struct kunit *test)
+{
+ const char *message_fmt = "lcm(%lu, %lu)";
+ const struct test_case *test_param = test->param_value;
+
+ KUNIT_EXPECT_EQ_MSG(test, test_param->result,
+ lcm(test_param->a, test_param->b),
+ message_fmt, test_param->a,
+ test_param->b);
+
+ if (test_param->a == test_param->b)
+ return;
+
+ /* lcm(a,b) == lcm(b,a) */
+ KUNIT_EXPECT_EQ_MSG(test, test_param->result,
+ lcm(test_param->b, test_param->a),
+ message_fmt, test_param->b,
+ test_param->a);
+}
+
+struct u32_test_case {
+ u32 a, b;
+ u32 result;
+};
+
+static struct u32_test_case reciprocal_div_cases[] = {
+ {
+ .a = 0, .b = 1,
+ .result = 0,
+ },
+ {
+ .a = 42, .b = 20,
+ .result = 2,
+ },
+ {
+ .a = 42, .b = 9999,
+ .result = 0,
+ },
+ {
+ .a = (1 << 16), .b = (1 << 14),
+ .result = 1 << 2,
+ },
+};
+
+KUNIT_ARRAY_PARAM(reciprocal_div, reciprocal_div_cases, NULL);
+
+static void reciprocal_div_test(struct kunit *test)
+{
+ const struct u32_test_case *test_param = test->param_value;
+ struct reciprocal_value rv = reciprocal_value(test_param->b);
+
+ KUNIT_EXPECT_EQ_MSG(test, test_param->result,
+ reciprocal_divide(test_param->a, rv),
+ "reciprocal_divide(%u, %u)",
+ test_param->a, test_param->b);
+}
+
+static void reciprocal_scale_test(struct kunit *test)
+{
+ KUNIT_EXPECT_EQ(test, reciprocal_scale(0u, 100), 0u);
+ KUNIT_EXPECT_EQ(test, reciprocal_scale(1u, 100), 0u);
+ KUNIT_EXPECT_EQ(test, reciprocal_scale(1u << 4, 1 << 28), 1u);
+ KUNIT_EXPECT_EQ(test, reciprocal_scale(1u << 16, 1 << 28), 1u << 12);
+ KUNIT_EXPECT_EQ(test, reciprocal_scale(~0u, 1 << 28), (1u << 28) - 1);
+}
+
+static struct kunit_case math_test_cases[] = {
+ KUNIT_CASE(abs_test),
+ KUNIT_CASE(int_sqrt_test),
+ KUNIT_CASE(round_up_test),
+ KUNIT_CASE(round_down_test),
+ KUNIT_CASE(roundup_test),
+ KUNIT_CASE(rounddown_test),
+ KUNIT_CASE(div_round_up_test),
+ KUNIT_CASE(div_round_closest_test),
+ KUNIT_CASE_PARAM(gcd_test, gcd_gen_params),
+ KUNIT_CASE_PARAM(lcm_test, lcm_gen_params),
+ KUNIT_CASE_PARAM(reciprocal_div_test, reciprocal_div_gen_params),
+ KUNIT_CASE(reciprocal_scale_test),
+ {}
+};
+
+static struct kunit_suite math_test_suite = {
+ .name = "lib-math",
+ .test_cases = math_test_cases,
+};
+
+kunit_test_suites(&math_test_suite);
+
+MODULE_DESCRIPTION("Math helper functions kunit test");
+MODULE_LICENSE("GPL");
--
2.39.1