1 files changed, 93 insertions, 0 deletions
diff --git a/libc/test/src/time/localtime_r_test.cpp b/libc/test/src/time/localtime_r_test.cpp
new file mode 100644
index 000000000000..8f7a79ef264a
--- /dev/null
+++ b/libc/test/src/time/localtime_r_test.cpp
@@ -0,0 +1,93 @@
+//===-- Unittests for localtime_r -----------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/time/localtime_r.h"
+#include "test/UnitTest/Test.h"
+
+TEST(LlvmLibcLocaltimeR, ValidUnixTimestamp0) {
+  struct tm input = {.tm_sec = 0,
+                     .tm_min = 0,
+                     .tm_hour = 0,
+                     .tm_mday = 0,
+                     .tm_mon = 0,
+                     .tm_year = 0,
+                     .tm_wday = 0,
+                     .tm_yday = 0,
+                     .tm_isdst = 0};
+  const time_t timer = 0;
+
+  struct tm *result = LIBC_NAMESPACE::localtime_r(&timer, &input);
+
+  ASSERT_EQ(70, result->tm_year);
+  ASSERT_EQ(0, result->tm_mon);
+  ASSERT_EQ(1, result->tm_mday);
+  ASSERT_EQ(0, result->tm_hour);
+  ASSERT_EQ(0, result->tm_min);
+  ASSERT_EQ(0, result->tm_sec);
+  ASSERT_EQ(4, result->tm_wday);
+  ASSERT_EQ(0, result->tm_yday);
+  ASSERT_EQ(0, result->tm_isdst);
+}
+
+TEST(LlvmLibcLocaltime, NullPtr) {
+  EXPECT_DEATH([] { LIBC_NAMESPACE::localtime_r(nullptr, nullptr); },
+               WITH_SIGNAL(4));
+}
+
+// TODO(zimirza): These tests does not expect the correct output of localtime as
+// per specification. This is due to timezone functions removed from
+// https://github.com/llvm/llvm-project/pull/110363.
+// This will be resolved a new pull request.
+
+TEST(LlvmLibcLocaltimeR, ValidUnixTimestamp) {
+  struct tm input = {.tm_sec = 0,
+                     .tm_min = 0,
+                     .tm_hour = 0,
+                     .tm_mday = 0,
+                     .tm_mon = 0,
+                     .tm_year = 0,
+                     .tm_wday = 0,
+                     .tm_yday = 0,
+                     .tm_isdst = 0};
+  const time_t timer = 1756595338;
+  struct tm *result = LIBC_NAMESPACE::localtime_r(&timer, &input);
+
+  ASSERT_EQ(125, result->tm_year);
+  ASSERT_EQ(7, result->tm_mon);
+  ASSERT_EQ(30, result->tm_mday);
+  ASSERT_EQ(23, result->tm_hour);
+  ASSERT_EQ(8, result->tm_min);
+  ASSERT_EQ(58, result->tm_sec);
+  ASSERT_EQ(6, result->tm_wday);
+  ASSERT_EQ(241, result->tm_yday);
+  ASSERT_EQ(0, result->tm_isdst);
+}
+
+TEST(LlvmLibcLocaltimeR, ValidUnixTimestampNegative) {
+  struct tm input = {.tm_sec = 0,
+                     .tm_min = 0,
+                     .tm_hour = 0,
+                     .tm_mday = 0,
+                     .tm_mon = 0,
+                     .tm_year = 0,
+                     .tm_wday = 0,
+                     .tm_yday = 0,
+                     .tm_isdst = 0};
+  const time_t timer = -1756595338;
+  struct tm *result = LIBC_NAMESPACE::localtime_r(&timer, &input);
+
+  ASSERT_EQ(14, result->tm_year);
+  ASSERT_EQ(4, result->tm_mon);
+  ASSERT_EQ(4, result->tm_mday);
+  ASSERT_EQ(0, result->tm_hour);
+  ASSERT_EQ(51, result->tm_min);
+  ASSERT_EQ(2, result->tm_sec);
+  ASSERT_EQ(1, result->tm_wday);
+  ASSERT_EQ(123, result->tm_yday);
+  ASSERT_EQ(0, result->tm_isdst);
+}