chromium/cc/metrics/average_lag_tracker_unittest.cc

// 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 "cc/metrics/average_lag_tracker.h"

#include <memory>

#include "base/test/metrics/histogram_tester.h"
#include "testing/gmock/include/gmock/gmock.h"
#include "testing/gtest/include/gtest/gtest.h"

Bucket;
ElementsAre;

namespace cc {
namespace {

class AverageLagTrackerTest : public testing::Test { … };

base::TimeTicks MillisecondsToTimeTicks(float t_ms) { … }

// Simulate a simple situation that events at every 10ms and start at t=15ms,
// frame swaps at every 10ms too and start at t=20ms and test we record one
// UMA for ScrollUpdate in one second.
TEST_F(AverageLagTrackerTest, OneSecondInterval) { … }

// Test the case that event's frame swap time is later than next event's
// creation time. (i.e, event at t=10ms will be dispatch at t=30ms, while next
// event is at t=20ms).
TEST_F(AverageLagTrackerTest, LargerLatency) { … }

// Test that multiple latency being flush in the same frame swap.
TEST_F(AverageLagTrackerTest, TwoLatencyInfoInSameFrame) { … }

// Test the case that switching direction causes lag at current frame
// time and previous frame time are in different direction.
TEST_F(AverageLagTrackerTest, ChangeDirectionInFrame) { … }

// A simple case without scroll prediction to compare with the two with
// prediction cases below.
TEST_F(AverageLagTrackerTest, NoScrollPrediction) { … }

// Test AverageLag with perfect scroll prediction.
TEST_F(AverageLagTrackerTest, ScrollPrediction) { … }

// Test AverageLag with imperfect scroll prediction.
TEST_F(AverageLagTrackerTest, ImperfectScrollPrediction) { … }

TEST_F(AverageLagTrackerTest, NegativePredictionEffect) { … }

TEST_F(AverageLagTrackerTest, NoPredictionEffect) { … }

// Tests that when an event arrives out-of-order, the average lag tracker
// properly ignores it.
TEST_F(AverageLagTrackerTest, EventOutOfOrder) { … }

}  // namespace
}  // namespace cc