base/time_unittest.cc

// Copyright 2008, Google Inc.
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//
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#include <time.h>

#if defined(OS_WIN)
#include <process.h>
#endif

#include "base/time.h"
#include "base/platform_thread.h"
#include "testing/gtest/include/gtest/gtest.h"

// Test conversions to/from time_t and exploding/unexploding.
TEST(Time, TimeT) {
  // C library time and exploded time.
  time_t now_t_1 = time(NULL);
  struct tm tms;
#if defined(OS_WIN)
  localtime_s(&tms, &now_t_1);
#elif defined(OS_POSIX)
  localtime_r(&now_t_1, &tms);
#endif

  // Convert to ours.
  Time our_time_1 = Time::FromTimeT(now_t_1);
  Time::Exploded exploded;
  our_time_1.LocalExplode(&exploded);

  // This will test both our exploding and our time_t -> Time conversion.
  EXPECT_EQ(tms.tm_year + 1900, exploded.year);
  EXPECT_EQ(tms.tm_mon + 1, exploded.month);
  EXPECT_EQ(tms.tm_mday, exploded.day_of_month);
  EXPECT_EQ(tms.tm_hour, exploded.hour);
  EXPECT_EQ(tms.tm_min, exploded.minute);
  EXPECT_EQ(tms.tm_sec, exploded.second);

  // Convert exploded back to the time struct.
  Time our_time_2 = Time::FromLocalExploded(exploded);
  EXPECT_TRUE(our_time_1 == our_time_2);

  time_t now_t_2 = our_time_2.ToTimeT();
  EXPECT_EQ(now_t_1, now_t_2);

  // Conversions of 0 should stay 0.
  EXPECT_EQ(0, Time().ToTimeT());
  EXPECT_EQ(0, Time::FromTimeT(0).ToInternalValue());
}

TEST(Time, ZeroIsSymmetric) {
  Time zeroTime(Time::FromTimeT(0));
  EXPECT_EQ(0, zeroTime.ToTimeT());
}

TEST(Time, LocalExplode) {
  Time a = Time::Now();
  Time::Exploded exploded;
  a.LocalExplode(&exploded);

  Time b = Time::FromLocalExploded(exploded);

  // The exploded structure doesn't have microseconds, so the result will be
  // rounded to the nearest millisecond.
  EXPECT_TRUE((a - b) < TimeDelta::FromMilliseconds(1));
}

TEST(Time, UTCExplode) {
  Time a = Time::Now();
  Time::Exploded exploded;
  a.UTCExplode(&exploded);

  Time b = Time::FromUTCExploded(exploded);
  EXPECT_TRUE((a - b) < TimeDelta::FromMilliseconds(1));
}

TEST(TimeTicks, Deltas) {
  TimeTicks ticks_start = TimeTicks::Now();
  PlatformThread::Sleep(10);
  TimeTicks ticks_stop = TimeTicks::Now();
  TimeDelta delta = ticks_stop - ticks_start;
  EXPECT_GE(delta.InMilliseconds(), 10);
  EXPECT_GE(delta.InMicroseconds(), 10000);
  EXPECT_EQ(delta.InSeconds(), 0);
}

#if defined(OS_WIN)

// TODO(pinkerton): Need to find a way to mock this for non-windows.

namespace {

class MockTimeTicks : public TimeTicks {
 public:
  static int Ticker() {
    return static_cast<int>(InterlockedIncrement(&ticker_));
  }

  static void InstallTicker() {
    old_tick_function_ = tick_function_;
    tick_function_ = reinterpret_cast<TickFunction>(&Ticker);
    ticker_ = -5;
  }

  static void UninstallTicker() {
    tick_function_ = old_tick_function_;
  }

 private:
  static volatile LONG ticker_;
  static TickFunction old_tick_function_;
};

volatile LONG MockTimeTicks::ticker_;
MockTimeTicks::TickFunction MockTimeTicks::old_tick_function_;

HANDLE g_rollover_test_start;

unsigned __stdcall RolloverTestThreadMain(void* param) {
  int64 counter = reinterpret_cast<int64>(param);
  DWORD rv = WaitForSingleObject(g_rollover_test_start, INFINITE);
  EXPECT_EQ(rv, WAIT_OBJECT_0);

  TimeTicks last = TimeTicks::Now();
  for (int index = 0; index < counter; index++) {
    TimeTicks now = TimeTicks::Now();
    int64 milliseconds = (now - last).InMilliseconds();
    EXPECT_GT(milliseconds, 0);
    EXPECT_LT(milliseconds, 250);
    last = now;
  }
  return 0;
}

} // namespace

TEST(TimeTicks, Rollover) {
  // The internal counter rolls over at ~49days.  We'll use a mock
  // timer to test this case.
  // Basic test algorithm:
  //   1) Set clock to rollover - N
  //   2) Create N threads
  //   3) Start the threads
  //   4) Each thread loops through TimeTicks() N times
  //   5) Each thread verifies integrity of result.

  const int kThreads = 8;
  // Use int64 so we can cast into a void* without a compiler warning.
  const int64 kChecks = 10;

  // It takes a lot of iterations to reproduce the bug!
  // (See bug 1081395)
  for (int loop = 0; loop < 4096; loop++) {
    // Setup
    MockTimeTicks::InstallTicker();
    g_rollover_test_start = CreateEvent(0, TRUE, FALSE, 0);
    HANDLE threads[kThreads];

    for (int index = 0; index < kThreads; index++) {
      void* argument = reinterpret_cast<void*>(kChecks);
      unsigned thread_id;
      threads[index] = reinterpret_cast<HANDLE>(
        _beginthreadex(NULL, 0, RolloverTestThreadMain, argument, 0,
          &thread_id));
      EXPECT_NE((HANDLE)NULL, threads[index]);
    }

    // Start!
    SetEvent(g_rollover_test_start);

    // Wait for threads to finish
    for (int index = 0; index < kThreads; index++) {
      DWORD rv = WaitForSingleObject(threads[index], INFINITE);
      EXPECT_EQ(rv, WAIT_OBJECT_0);
    }

    CloseHandle(g_rollover_test_start);

    // Teardown
    MockTimeTicks::UninstallTicker();
  }
}

#endif