lib/math/rational-test.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include <kunit/test.h>
   4
   5 #include <linux/rational.h>
   6
   7 struct rational_test_param {
   8         unsigned long num, den;
   9         unsigned long max_num, max_den;
  10         unsigned long exp_num, exp_den;
  11
  12         const char *name;
  13 };
  14
  15 static const struct rational_test_param test_parameters[] = {
  16         { 1230, 10,     100, 20,        100, 1,    "Exceeds bounds, semi-convergent term > 1/2 last term" },
  17         { 34567,100,    120, 20,        120, 1,    "Exceeds bounds, semi-convergent term < 1/2 last term" },
  18         { 1, 30,        100, 10,        0, 1,      "Closest to zero" },
  19         { 1, 19,        100, 10,        1, 10,     "Closest to smallest non-zero" },
  20         { 27,32,        16, 16,         11, 13,    "Use convergent" },
  21         { 1155, 7735,   255, 255,       33, 221,   "Exact answer" },
  22         { 87, 32,       70, 32,         68, 25,    "Semiconvergent, numerator limit" },
  23         { 14533, 4626,  15000, 2400,    7433, 2366, "Semiconvergent, denominator limit" },
  24 };
  25
  26 static void get_desc(const struct rational_test_param *param, char *desc)
  27 {
  28         strscpy(desc, param->name, KUNIT_PARAM_DESC_SIZE);
  29 }
  30
  31 /* Creates function rational_gen_params */
  32 KUNIT_ARRAY_PARAM(rational, test_parameters, get_desc);
  33
  34 static void rational_test(struct kunit *test)
  35 {
  36         const struct rational_test_param *param = (const struct rational_test_param *)test->param_value;
  37         unsigned long n = 0, d = 0;
  38
  39         rational_best_approximation(param->num, param->den, param->max_num, param->max_den, &n, &d);
  40         KUNIT_EXPECT_EQ(test, n, param->exp_num);
  41         KUNIT_EXPECT_EQ(test, d, param->exp_den);
  42 }
  43
  44 static struct kunit_case rational_test_cases[] = {
  45         KUNIT_CASE_PARAM(rational_test, rational_gen_params),
  46         {}
  47 };
  48
  49 static struct kunit_suite rational_test_suite = {
  50         .name = "rational",
  51         .test_cases = rational_test_cases,
  52 };
  53
  54 kunit_test_suites(&rational_test_suite);
  55
  56 MODULE_DESCRIPTION("Rational fractions unit test");
  57 MODULE_LICENSE("GPL v2");