Implemented a proper clock for audio/video synchronization.

media/base/clock_impl_unittest.cc

+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/logging.h"
+#include "media/base/clock_impl.h"
+#include "testing/gmock/include/gmock/gmock.h"
+
+using ::testing::DefaultValue;
+using ::testing::InSequence;
+using ::testing::Return;
+using ::testing::StrictMock;
+
+namespace {
+
+// Provide a stream output operator so we can use EXPECT_EQ(...) with TimeDelta.
+//
+// TODO(scherkus): move this into the testing package.
+std::ostream& operator<<(std::ostream& stream, const base::TimeDelta& time) {
+  return (stream << time.ToInternalValue());
+}
+
+}  // namespace
+
+namespace media {
+
+class MockTimeProvider {
+ public:
+  MockTimeProvider() {
+    DCHECK(!instance_) << "Only one instance of MockTimeProvider can exist";
+    DCHECK(!DefaultValue<base::Time>::IsSet());
+    instance_ = this;
+    DefaultValue<base::Time>::Set(base::Time::FromInternalValue(0));
+  }
+
+  ~MockTimeProvider() {
+    instance_ = NULL;
+    DefaultValue<base::Time>::Clear();
+  }
+
+  MOCK_METHOD0(Now, base::Time());
+
+  static base::Time StaticNow() {
+    return instance_->Now();
+  }
+
+ private:
+  static MockTimeProvider* instance_;
+  DISALLOW_COPY_AND_ASSIGN(MockTimeProvider);
+};
+
+MockTimeProvider* MockTimeProvider::instance_ = NULL;
+
+TEST(ClockTest, Created) {
+  StrictMock<MockTimeProvider> mock_time;
+  const base::TimeDelta kExpected = base::TimeDelta::FromSeconds(0);
+
+  ClockImpl clock(&MockTimeProvider::StaticNow);
+  EXPECT_EQ(kExpected, clock.Elapsed());
+}
+
+TEST(ClockTest, Play_NormalSpeed) {
+  InSequence s;
+  StrictMock<MockTimeProvider> mock_time;
+  EXPECT_CALL(mock_time, Now())
+      .WillOnce(Return(base::Time::FromDoubleT(4)));
+  EXPECT_CALL(mock_time, Now())
+      .WillOnce(Return(base::Time::FromDoubleT(6)));
+  const base::TimeDelta kZero;
+  const base::TimeDelta kExpected = base::TimeDelta::FromSeconds(2);
+
+  ClockImpl clock(&MockTimeProvider::StaticNow);
+  EXPECT_EQ(kZero, clock.Play());
+  EXPECT_EQ(kExpected, clock.Elapsed());
+}
+
+TEST(ClockTest, Play_DoubleSpeed) {
+  InSequence s;
+  StrictMock<MockTimeProvider> mock_time;
+  EXPECT_CALL(mock_time, Now())
+      .WillOnce(Return(base::Time::FromDoubleT(4)));
+  EXPECT_CALL(mock_time, Now())
+      .WillOnce(Return(base::Time::FromDoubleT(9)));
+  const base::TimeDelta kZero;
+  const base::TimeDelta kExpected = base::TimeDelta::FromSeconds(10);
+
+  ClockImpl clock(&MockTimeProvider::StaticNow);
+  clock.SetPlaybackRate(2.0f);
+  EXPECT_EQ(kZero, clock.Play());
+  EXPECT_EQ(kExpected, clock.Elapsed());
+}
+
+TEST(ClockTest, Play_HalfSpeed) {
+  InSequence s;
+  StrictMock<MockTimeProvider> mock_time;
+  EXPECT_CALL(mock_time, Now())
+      .WillOnce(Return(base::Time::FromDoubleT(4)));
+  EXPECT_CALL(mock_time, Now())
+      .WillOnce(Return(base::Time::FromDoubleT(8)));
+  const base::TimeDelta kZero;
+  const base::TimeDelta kExpected = base::TimeDelta::FromSeconds(2);
+
+  ClockImpl clock(&MockTimeProvider::StaticNow);
+  clock.SetPlaybackRate(0.5f);
+  EXPECT_EQ(kZero, clock.Play());
+  EXPECT_EQ(kExpected, clock.Elapsed());
+}
+
+TEST(ClockTest, Play_ZeroSpeed) {
+  // We'll play for 2 seconds at normal speed, 4 seconds at zero speed, and 8
+  // seconds at normal speed:
+  //   (1.0 x 2) + (0.0 x 4) + (1.0 x 8) = 10
+  InSequence s;
+  StrictMock<MockTimeProvider> mock_time;
+  EXPECT_CALL(mock_time, Now())
+      .WillOnce(Return(base::Time::FromDoubleT(4)));
+  EXPECT_CALL(mock_time, Now())
+      .WillOnce(Return(base::Time::FromDoubleT(6)));
+  EXPECT_CALL(mock_time, Now())
+      .WillOnce(Return(base::Time::FromDoubleT(10)));
+  EXPECT_CALL(mock_time, Now())
+      .WillOnce(Return(base::Time::FromDoubleT(18)));
+  const base::TimeDelta kZero;
+  const base::TimeDelta kExpected = base::TimeDelta::FromSeconds(10);
+
+  ClockImpl clock(&MockTimeProvider::StaticNow);
+  EXPECT_EQ(kZero, clock.Play());
+  clock.SetPlaybackRate(0.0f);
+  clock.SetPlaybackRate(1.0f);
+  EXPECT_EQ(kExpected, clock.Elapsed());
+}
+
+TEST(ClockTest, Play_MultiSpeed) {
+  // We'll play for 2 seconds at half speed, 4 seconds at normal speed, and 8
+  // seconds at double speed:
+  //   (0.5 x 2) + (1.0 x 4) + (2.0 x 8) = 21
+  InSequence s;
+  StrictMock<MockTimeProvider> mock_time;
+  EXPECT_CALL(mock_time, Now())
+      .WillOnce(Return(base::Time::FromDoubleT(4)));
+  EXPECT_CALL(mock_time, Now())
+      .WillOnce(Return(base::Time::FromDoubleT(6)));
+  EXPECT_CALL(mock_time, Now())
+      .WillOnce(Return(base::Time::FromDoubleT(10)));
+  EXPECT_CALL(mock_time, Now())
+      .WillOnce(Return(base::Time::FromDoubleT(18)));
+  const base::TimeDelta kZero;
+  const base::TimeDelta kExpected = base::TimeDelta::FromSeconds(21);
+
+  ClockImpl clock(&MockTimeProvider::StaticNow);
+  clock.SetPlaybackRate(0.5f);
+  EXPECT_EQ(kZero, clock.Play());
+  clock.SetPlaybackRate(1.0f);
+  clock.SetPlaybackRate(2.0f);
+  EXPECT_EQ(kExpected, clock.Elapsed());
+}
+
+TEST(ClockTest, Pause) {
+  InSequence s;
+  StrictMock<MockTimeProvider> mock_time;
+  EXPECT_CALL(mock_time, Now())
+      .WillOnce(Return(base::Time::FromDoubleT(4)));
+  EXPECT_CALL(mock_time, Now())
+      .WillOnce(Return(base::Time::FromDoubleT(8)));
+  EXPECT_CALL(mock_time, Now())
+      .WillOnce(Return(base::Time::FromDoubleT(12)));
+  EXPECT_CALL(mock_time, Now())
+      .WillOnce(Return(base::Time::FromDoubleT(16)));
+  const base::TimeDelta kZero;
+  const base::TimeDelta kFirstPause = base::TimeDelta::FromSeconds(4);
+  const base::TimeDelta kSecondPause = base::TimeDelta::FromSeconds(8);
+
+  ClockImpl clock(&MockTimeProvider::StaticNow);
+  EXPECT_EQ(kZero, clock.Play());
+  EXPECT_EQ(kFirstPause, clock.Pause());
+  EXPECT_EQ(kFirstPause, clock.Elapsed());
+  EXPECT_EQ(kFirstPause, clock.Play());
+  EXPECT_EQ(kSecondPause, clock.Pause());
+  EXPECT_EQ(kSecondPause, clock.Elapsed());
+}
+
+TEST(ClockTest, SetTime_Paused) {
+  // We'll remain paused while we set the time.  The time should be simply
+  // updated without accessing the time provider.
+  InSequence s;
+  StrictMock<MockTimeProvider> mock_time;
+  const base::TimeDelta kFirstTime = base::TimeDelta::FromSeconds(4);
+  const base::TimeDelta kSecondTime = base::TimeDelta::FromSeconds(16);
+
+  ClockImpl clock(&MockTimeProvider::StaticNow);
+  clock.SetTime(kFirstTime);
+  EXPECT_EQ(kFirstTime, clock.Elapsed());
+  clock.SetTime(kSecondTime);
+  EXPECT_EQ(kSecondTime, clock.Elapsed());
+}
+
+TEST(ClockTest, SetTime_Playing) {
+  // We'll play for 4 seconds, then set the time to 12, then play for 4 more
+  // seconds.  We'll expect a media time of 16.
+  InSequence s;
+  StrictMock<MockTimeProvider> mock_time;
+  EXPECT_CALL(mock_time, Now())
+      .WillOnce(Return(base::Time::FromDoubleT(4)));
+  EXPECT_CALL(mock_time, Now())
+      .WillOnce(Return(base::Time::FromDoubleT(8)));
+  EXPECT_CALL(mock_time, Now())
+      .WillOnce(Return(base::Time::FromDoubleT(12)));
+  const base::TimeDelta kZero;
+  const base::TimeDelta kExepected = base::TimeDelta::FromSeconds(16);
+
+  ClockImpl clock(&MockTimeProvider::StaticNow);
+  EXPECT_EQ(kZero, clock.Play());
+  clock.SetTime(base::TimeDelta::FromSeconds(12));
+  EXPECT_EQ(kExepected, clock.Elapsed());
+}
+
+}  // namespace media