1 files changed, 91 insertions, 0 deletions
diff --git a/tests/xtimegm.c b/tests/xtimegm.c
new file mode 100644
index 0000000..2426815
--- /dev/null
+++ b/tests/xtimegm.c
@@ -0,0 +1,91 @@
+#include "../time.h"
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+static bool tm_equal(const struct tm *tma, const struct tm *tmb) {
+	if (tma->tm_year != tmb->tm_year) {
+		return false;
+	}
+	if (tma->tm_mon != tmb->tm_mon) {
+		return false;
+	}
+	if (tma->tm_mday != tmb->tm_mday) {
+		return false;
+	}
+	if (tma->tm_hour != tmb->tm_hour) {
+		return false;
+	}
+	if (tma->tm_min != tmb->tm_min) {
+		return false;
+	}
+	if (tma->tm_sec != tmb->tm_sec) {
+		return false;
+	}
+	if (tma->tm_wday != tmb->tm_wday) {
+		return false;
+	}
+	if (tma->tm_yday != tmb->tm_yday) {
+		return false;
+	}
+	if (tma->tm_isdst != tmb->tm_isdst) {
+		return false;
+	}
+
+	return true;
+}
+
+static void tm_print(FILE *file, const struct tm *tm) {
+	fprintf(file, "Y%d M%d D%d  h%d m%d s%d  wd%d yd%d%s\n",
+	        tm->tm_year, tm->tm_mon, tm->tm_mday,
+	        tm->tm_hour, tm->tm_min, tm->tm_sec,
+	        tm->tm_wday, tm->tm_yday,
+		tm->tm_isdst ? (tm->tm_isdst < 0 ? " (DST?)" : " (DST)") : "");
+}
+
+int main(void) {
+	if (setenv("TZ", "UTC0", true) != 0) {
+		perror("setenv()");
+		return EXIT_FAILURE;
+	}
+
+	struct tm tm = {
+		.tm_isdst = -1,
+	};
+
+	for (tm.tm_year = 0; tm.tm_year <= 200; tm.tm_year += 10)
+	for (tm.tm_mon = -3; tm.tm_mon <= 15; tm.tm_mon += 3)
+	for (tm.tm_mday = -31; tm.tm_mday <= 61; tm.tm_mday += 4)
+	for (tm.tm_hour = -1; tm.tm_hour <= 24; tm.tm_hour += 5)
+	for (tm.tm_min = -1; tm.tm_min <= 60; tm.tm_min += 31)
+	for (tm.tm_sec = -60; tm.tm_sec <= 120; tm.tm_sec += 5) {
+		struct tm tma = tm, tmb = tm;
+		time_t ta, tb;
+		ta = mktime(&tma);
+		if (xtimegm(&tmb, &tb) != 0) {
+			tb = -1;
+		}
+
+		bool fail = false;
+		if (ta != tb) {
+			printf("Mismatch:  %jd != %jd\n", (intmax_t)ta, (intmax_t)tb);
+			fail = true;
+		}
+		if (ta != -1 && !tm_equal(&tma, &tmb)) {
+			printf("mktime():  ");
+			tm_print(stdout, &tma);
+			printf("xtimegm(): ");
+			tm_print(stdout, &tmb);
+			fail = true;
+		}
+		if (fail) {
+			printf("Input:     ");
+			tm_print(stdout, &tm);
+			return EXIT_FAILURE;
+		}
+	}
+
+	return EXIT_SUCCESS;
+}