xtime: Call tzset() from main() instead of lazily

POSIX specifies[1] that

    If a thread accesses tzname, daylight, or timezone directly while
    another thread is in a call to tzset(), or to any function that is
    required or allowed to set timezone information as if by calling
    tzset(), the behavior is undefined.

So calling it lazily from arbitrary threads is risky.

[1]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/tzset.html

1 files changed, 14 insertions, 0 deletions

diff --git a/tests/main.c b/tests/main.c
index e69fe35..38438b2 100644
--- a/tests/main.c
+++ b/tests/main.c
@@ -11,9 +11,11 @@
 #include "../src/config.h"
 #include "../src/diag.h"
 #include <errno.h>
+#include <locale.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <time.h>
 
 /**
  * Test context.
@@ -90,6 +92,18 @@ static void run_test(struct test_ctx *ctx, const char *test, test_fn *fn) {
 }
 
 int main(int argc, char *argv[]) {
+	// Try to set a UTF-8 locale
+	if (!setlocale(LC_ALL, "C.UTF-8")) {
+		setlocale(LC_ALL, "");
+	}
+
+	// Run tests in UTC
+	if (setenv("TZ", "UTC0", true) != 0) {
+		perror("setenv()");
+		return EXIT_FAILURE;
+	}
+	tzset();
+
 	struct test_ctx ctx;
 	if (test_init(&ctx, argc, argv) != 0) {
 		goto done;