// SPDX-License-Identifier: GPL-2.0

#include <kunit/test.h>

#include <linux/rational.h>

struct rational_test_param {
        unsigned long num, den;
        unsigned long max_num, max_den;
        unsigned long exp_num, exp_den;

        const char *name;
};

static const struct rational_test_param test_parameters[] = {
        { 1230, 10,     100, 20,        100, 1,    "Exceeds bounds, semi-convergent term > 1/2 last term" },
        { 34567,100,    120, 20,        120, 1,    "Exceeds bounds, semi-convergent term < 1/2 last term" },
        { 1, 30,        100, 10,        0, 1,      "Closest to zero" },
        { 1, 19,        100, 10,        1, 10,     "Closest to smallest non-zero" },
        { 27,32,        16, 16,         11, 13,    "Use convergent" },
        { 1155, 7735,   255, 255,       33, 221,   "Exact answer" },
        { 87, 32,       70, 32,         68, 25,    "Semiconvergent, numerator limit" },
        { 14533, 4626,  15000, 2400,    7433, 2366, "Semiconvergent, denominator limit" },
};

static void get_desc(const struct rational_test_param *param, char *desc)
{
        strscpy(desc, param->name, KUNIT_PARAM_DESC_SIZE);
}

/* Creates function rational_gen_params */
KUNIT_ARRAY_PARAM(rational, test_parameters, get_desc);

static void rational_test(struct kunit *test)
{
        const struct rational_test_param *param = (const struct rational_test_param *)test->param_value;
        unsigned long n = 0, d = 0;

        rational_best_approximation(param->num, param->den, param->max_num, param->max_den, &n, &d);
        KUNIT_EXPECT_EQ(test, n, param->exp_num);
        KUNIT_EXPECT_EQ(test, d, param->exp_den);
}

static struct kunit_case rational_test_cases[] = {
        KUNIT_CASE_PARAM(rational_test, rational_gen_params),
        {}
};

static struct kunit_suite rational_test_suite = {
        .name = "rational",
        .test_cases = rational_test_cases,
};

kunit_test_suites(&rational_test_suite);

MODULE_DESCRIPTION("Rational fractions unit test");
MODULE_LICENSE("GPL v2");