1 files changed, 36 insertions, 0 deletions
diff --git a/libc/test/src/time/clock_gettime_test.cpp b/libc/test/src/time/clock_gettime_test.cpp
new file mode 100644
index 000000000000..3214ca19c72a
--- /dev/null
+++ b/libc/test/src/time/clock_gettime_test.cpp
@@ -0,0 +1,36 @@
+//===-- Unittests for clock_gettime ---------------------------------------===//
+//
+// 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/clock_gettime.h"
+#include "utils/UnitTest/Test.h"
+
+#include <time.h>
+
+TEST(LlvmLibcClockGetTime, RealTime) {
+  struct timespec tp;
+  int result;
+  result = clock_gettime(CLOCK_REALTIME, &tp);
+  ASSERT_EQ(result, 0);
+  ASSERT_GT(tp.tv_sec, time_t(0));
+}
+
+#ifdef CLOCK_MONOTONIC
+TEST(LlvmLibcClockGetTime, MonotonicTime) {
+  struct timespec tp1, tp2;
+  int result;
+  result = clock_gettime(CLOCK_MONOTONIC, &tp1);
+  ASSERT_EQ(result, 0);
+  ASSERT_GT(tp1.tv_sec, time_t(0));
+  result = clock_gettime(CLOCK_MONOTONIC, &tp2);
+  ASSERT_EQ(result, 0);
+  ASSERT_GE(tp2.tv_sec, tp1.tv_sec); // The monotonic clock should increase.
+  if (tp2.tv_sec == tp1.tv_sec) {
+    ASSERT_GE(tp2.tv_nsec, tp1.tv_nsec);
+  }
+}
+#endif // CLOCK_MONOTONIC