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lib: add basic KUnit test for lib/math 
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>
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@dlatypov @intel-lab-lkp
dlatypov authored and intel-lab-lkp committed Apr 16, 2021
1 parent 7e25f40 commit 0f1888ffeaa6baa1bc2a99eac8ba7d1df29c8450
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12 lib/math/Kconfig
View file
@@ -15,3 +15,15 @@ config PRIME_NUMBERS

config RATIONAL
bool

config MATH_KUNIT_TEST
tristate "KUnit test for lib/math and math.h" if !KUNIT_ALL_TESTS
depends on KUNIT
default KUNIT_ALL_TESTS
help
This builds unit tests for 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.
2 lib/math/Makefile
View file
@@ -4,3 +4,5 @@ obj-y += div64.o gcd.o lcm.o int_pow.o int_sqrt.o reciprocal_div.o
obj-$(CONFIG_CORDIC) += cordic.o
obj-$(CONFIG_PRIME_NUMBERS) += prime_numbers.o
obj-$(CONFIG_RATIONAL) += rational.o

obj-$(CONFIG_MATH_KUNIT_TEST) += math_kunit.o
291 lib/math/math_kunit.c
View file
@@ -0,0 +1,291 @@
// 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/kernel.h>
#include <linux/lcm.h>
#include <linux/reciprocal_div.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_LICENSE("GPL v2");

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