1 // SPDX-License-Identifier: LGPL-2.1+
2
3 #include <kunit/test.h>
4 #include <linux/time.h>
5
6 /*
7 * Traditional implementation of leap year evaluation.
8 */
is_leap(long year)9 static bool is_leap(long year)
10 {
11 return year % 4 == 0 && (year % 100 != 0 || year % 400 == 0);
12 }
13
14 /*
15 * Gets the last day of a month.
16 */
last_day_of_month(long year,int month)17 static int last_day_of_month(long year, int month)
18 {
19 if (month == 2)
20 return 28 + is_leap(year);
21 if (month == 4 || month == 6 || month == 9 || month == 11)
22 return 30;
23 return 31;
24 }
25
26 /*
27 * Advances a date by one day.
28 */
advance_date(long * year,int * month,int * mday,int * yday)29 static void advance_date(long *year, int *month, int *mday, int *yday)
30 {
31 if (*mday != last_day_of_month(*year, *month)) {
32 ++*mday;
33 ++*yday;
34 return;
35 }
36
37 *mday = 1;
38 if (*month != 12) {
39 ++*month;
40 ++*yday;
41 return;
42 }
43
44 *month = 1;
45 *yday = 0;
46 ++*year;
47 }
48
49 /*
50 * Checks every day in a 160000 years interval centered at 1970-01-01
51 * against the expected result.
52 */
time64_to_tm_test_date_range(struct kunit * test)53 static void time64_to_tm_test_date_range(struct kunit *test)
54 {
55 /*
56 * 80000 years = (80000 / 400) * 400 years
57 * = (80000 / 400) * 146097 days
58 * = (80000 / 400) * 146097 * 86400 seconds
59 */
60 time64_t total_secs = ((time64_t) 80000) / 400 * 146097 * 86400;
61 long year = 1970 - 80000;
62 int month = 1;
63 int mdday = 1;
64 int yday = 0;
65
66 struct tm result;
67 time64_t secs;
68 s64 days;
69
70 for (secs = -total_secs; secs <= total_secs; secs += 86400) {
71
72 time64_to_tm(secs, 0, &result);
73
74 days = div_s64(secs, 86400);
75
76 #define FAIL_MSG "%05ld/%02d/%02d (%2d) : %lld", \
77 year, month, mdday, yday, days
78
79 KUNIT_ASSERT_EQ_MSG(test, year - 1900, result.tm_year, FAIL_MSG);
80 KUNIT_ASSERT_EQ_MSG(test, month - 1, result.tm_mon, FAIL_MSG);
81 KUNIT_ASSERT_EQ_MSG(test, mdday, result.tm_mday, FAIL_MSG);
82 KUNIT_ASSERT_EQ_MSG(test, yday, result.tm_yday, FAIL_MSG);
83
84 advance_date(&year, &month, &mdday, &yday);
85 }
86 }
87
88 static struct kunit_case time_test_cases[] = {
89 KUNIT_CASE_SLOW(time64_to_tm_test_date_range),
90 {}
91 };
92
93 static struct kunit_suite time_test_suite = {
94 .name = "time_test_cases",
95 .test_cases = time_test_cases,
96 };
97
98 kunit_test_suite(time_test_suite);
99 MODULE_DESCRIPTION("time unit test suite");
100 MODULE_LICENSE("GPL");
101