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base / timer / lap_timer_unittest.cc [blame]
// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/timer/lap_timer.h"
#include "base/test/task_environment.h"
#include "base/time/time.h"
#include "build/build_config.h"
#include "testing/gtest/include/gtest/gtest.h"
// This file contains a minimal unit test for LapTimer, used for benchmarking.
// This file is supposed to match closely with the example code, documented in
// lap_timer.h. Please update that documentation if you need to change things.
namespace base {
namespace test {
namespace {
constexpr base::TimeDelta kTimeLimit = base::Milliseconds(15);
constexpr base::TimeDelta kTimeAdvance = base::Milliseconds(1);
constexpr int kWarmupRuns = 5;
constexpr int kTimeCheckInterval = 10;
} // namespace
TEST(LapTimer, UsageExample) {
TaskEnvironment task_environment(TaskEnvironment::TimeSource::MOCK_TIME);
LapTimer timer(kWarmupRuns, kTimeLimit, kTimeCheckInterval);
EXPECT_FALSE(timer.HasTimeLimitExpired());
EXPECT_FALSE(timer.IsWarmedUp());
do {
task_environment.FastForwardBy(kTimeAdvance);
timer.NextLap();
} while (!timer.HasTimeLimitExpired());
EXPECT_NEAR(timer.LapsPerSecond(), 1000, 0.1);
EXPECT_NEAR(timer.TimePerLap().InMillisecondsF(), 1.0f, 0.1);
// Output number of laps is 20, because the warm up runs are ignored and the
// timer is only checked every kTimeInterval laps.
EXPECT_EQ(timer.NumLaps(), 20);
EXPECT_TRUE(timer.HasTimeLimitExpired());
EXPECT_TRUE(timer.IsWarmedUp());
}
#if !BUILDFLAG(IS_IOS)
// iOS simulator does not support using ThreadTicks.
TEST(LapTimer, ThreadTicksUsageExample) {
TaskEnvironment task_environment(TaskEnvironment::TimeSource::MOCK_TIME);
LapTimer timer(kWarmupRuns, kTimeLimit, kTimeCheckInterval,
LapTimer::TimerMethod::kUseThreadTicks);
EXPECT_FALSE(timer.HasTimeLimitExpired());
EXPECT_FALSE(timer.IsWarmedUp());
do {
task_environment.FastForwardBy(kTimeAdvance);
timer.NextLap();
} while (!timer.HasTimeLimitExpired());
// Because advancing the TaskEnvironment time won't affect the
// ThreadTicks, laps will be much faster than the regular UsageExample.
EXPECT_GT(timer.LapsPerSecond(), 1000);
EXPECT_LT(timer.TimePerLap().InMillisecondsF(), 1.0f);
EXPECT_GT(timer.NumLaps(), 20);
EXPECT_TRUE(timer.HasTimeLimitExpired());
EXPECT_TRUE(timer.IsWarmedUp());
}
#endif
} // namespace test
} // namespace base