Add test case for clock_gettime

test/cpp-utils/CMakeLists.txt

@@ -45,6 +45,7 @@ set(SOURCES
     assert/backtrace_include_test.cpp
     assert/assert_include_test.cpp
     assert/assert_debug_test.cpp
+    system/ClockGetTimeTest.cpp
     system/MemoryTest.cpp
     system/HomedirTest.cpp
 )

test/cpp-utils/system/ClockGetTimeTest.cpp

@@ -0,0 +1,40 @@
+#include <gtest/gtest.h>
+#include <cpp-utils/system/clock_gettime.h>
+#include <chrono>
+#include <thread>
+
+namespace {
+struct timespec _gettime() {
+    struct timespec current_time;
+    int res = clock_gettime(CLOCK_REALTIME, &current_time);
+    EXPECT_EQ(0, res);
+    return current_time;
+}
+
+uint64_t _to_nanos(struct timespec time) {
+    constexpr uint64_t nanos = UINT64_C(1000000000);
+    return time.tv_sec * nanos + time.tv_nsec;
+}
+}
+
+TEST(ClockGetTimeTest, DoesntCrash) {
+    _gettime();
+}
+
+TEST(ClockGetTimeTest, IsLaterThanYear2010) {
+    struct timespec current_time = _gettime();
+    EXPECT_LT(1262304000, current_time.tv_sec);
+}
+
+TEST(ClockGetTimeTest, IsNondecreasing) {
+    uint64_t time1 = _to_nanos(_gettime());
+    uint64_t time2 = _to_nanos(_gettime());
+    EXPECT_LE(time1, time2);
+}
+
+TEST(ClockGetTimeTest, IsIncreasedAfterPause) {
+    uint64_t time1 = _to_nanos(_gettime());
+    std::this_thread::sleep_for(std::chrono::milliseconds(10));
+    uint64_t time2 = _to_nanos(_gettime());
+    EXPECT_LT(time1, time2);
+}