TestTimeStamp.cpp - mozsearch

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/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "mozilla/TimeStamp.h"

#include "prinrval.h"

#include "prthread.h"

#include "gtest/gtest.h"

using mozilla::TimeDuration;

using mozilla::TimeStamp;

TEST(TimeStamp, Main)

  TimeDuration td;

  EXPECT_TRUE(td.ToSeconds() == 0.0);

  EXPECT_TRUE(TimeDuration::FromSeconds(5).ToSeconds() == 5.0);

  EXPECT_TRUE(TimeDuration::FromMilliseconds(5000).ToSeconds() == 5.0);

  EXPECT_TRUE(TimeDuration::FromSeconds(1) < TimeDuration::FromSeconds(2));

  EXPECT_FALSE(TimeDuration::FromSeconds(1) < TimeDuration::FromSeconds(1));

  EXPECT_TRUE(TimeDuration::FromSeconds(2) > TimeDuration::FromSeconds(1));

  EXPECT_FALSE(TimeDuration::FromSeconds(1) > TimeDuration::FromSeconds(1));

  EXPECT_TRUE(TimeDuration::FromSeconds(1) <= TimeDuration::FromSeconds(2));

  EXPECT_TRUE(TimeDuration::FromSeconds(1) <= TimeDuration::FromSeconds(1));

  EXPECT_FALSE(TimeDuration::FromSeconds(2) <= TimeDuration::FromSeconds(1));

  EXPECT_TRUE(TimeDuration::FromSeconds(2) >= TimeDuration::FromSeconds(1));

  EXPECT_TRUE(TimeDuration::FromSeconds(1) >= TimeDuration::FromSeconds(1));

  EXPECT_FALSE(TimeDuration::FromSeconds(1) >= TimeDuration::FromSeconds(2));

  TimeStamp ts;

  EXPECT_TRUE(ts.IsNull());

  ts = TimeStamp::Now();

  EXPECT_TRUE(!ts.IsNull());

  EXPECT_TRUE((ts - ts).ToSeconds() == 0.0);

  PR_Sleep(PR_SecondsToInterval(2));

  TimeStamp ts2(TimeStamp::Now());

  EXPECT_TRUE(ts2 > ts);

  EXPECT_FALSE(ts > ts);

  EXPECT_TRUE(ts < ts2);

  EXPECT_FALSE(ts < ts);

  EXPECT_TRUE(ts <= ts2);

  EXPECT_TRUE(ts <= ts);

  EXPECT_FALSE(ts2 <= ts);

  EXPECT_TRUE(ts2 >= ts);

  EXPECT_TRUE(ts2 >= ts);

  EXPECT_FALSE(ts >= ts2);

  // We can't be sure exactly how long PR_Sleep slept for. It should have

  // slept for at least one second. We might have slept a lot longer due

  // to process scheduling, but hopefully not more than 10 seconds.

  td = ts2 - ts;

  EXPECT_TRUE(td.ToSeconds() > 1.0);

  EXPECT_TRUE(td.ToSeconds() < 20.0);

  td = ts - ts2;

  EXPECT_TRUE(td.ToSeconds() < -1.0);

  EXPECT_TRUE(td.ToSeconds() > -20.0);

  // Now() is trying to ensure the best possible precision on each platform,

  // but guarantees at least one millisecond resolution. Given the huge

  // difference between the assumed resolution of the clock on modern CPUs

  // (< 100ns, often close to 1ns as of 2025) and that guarantee, we can safely

  // test for 1ms without fearing intermittents caused by jitter.

  TimeStamp start = TimeStamp::Now();

  TimeStamp last = start;

  int updated = 0;

  int same = 0;

  while ((last - start).ToMilliseconds() < 1.0) {

    TimeStamp next = TimeStamp::Now();

    if ((next - last).ToMicroseconds() > 0.0) {

      // Only count if we saw progress in the ticks.

      ++updated;

      last = next;

    } else {

      ++same;

  printf("  Poll saw updated iterations in 1ms: %d\n", updated);

  printf("  Poll saw same iterations in 1ms: %d\n", same);

  // If we saw 2 updates, we can be pretty sure to be able to guarantee at

  // least 1ms resolution. In practice we see much higher numbers here (>>1K).

  EXPECT_GE(updated, 2);