1 files changed, 189 insertions, 0 deletions
diff --git a/dom/media/gtest/TestPacer.cpp b/dom/media/gtest/TestPacer.cpp
new file mode 100644
index 0000000000..df9bb4c9e5
--- /dev/null
+++ b/dom/media/gtest/TestPacer.cpp
@@ -0,0 +1,189 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* 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 "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "mozilla/gtest/WaitFor.h"
+#include "Pacer.h"
+#include "VideoUtils.h"
+
+using namespace mozilla;
+
+template <typename T>
+class PacerTest {
+ protected:
+  explicit PacerTest(TimeDuration aDuplicationInterval)
+      : mTaskQueue(TaskQueue::Create(
+            GetMediaThreadPool(MediaThreadType::WEBRTC_WORKER), "PacerTest")),
+        mPacer(MakeRefPtr<Pacer<T>>(mTaskQueue, aDuplicationInterval)),
+        mInterval(aDuplicationInterval) {}
+
+  // Helper for calling `mPacer->Enqueue(...)`. Dispatches an event to the
+  // current thread which will enqueue the event to make sure that any listeners
+  // registered by a call to `WaitFor(...)` have been registered before events
+  // start being processed on a background queue.
+  void EnqueueSoon(T aItem, TimeStamp aTime) {
+    MOZ_ALWAYS_SUCCEEDS(NS_DispatchToCurrentThread(NS_NewRunnableFunction(
+        "PacerTest::EnqueueSoon",
+        [pacer = mPacer, aItem = std::move(aItem), aTime] {
+          pacer->Enqueue(std::move(aItem), aTime);
+        })));
+  }
+
+  void TearDown() {
+    mPacer->Shutdown()->Then(mTaskQueue, __func__,
+                             [tq = mTaskQueue] { tq->BeginShutdown(); });
+  }
+
+  const RefPtr<TaskQueue> mTaskQueue;
+  const RefPtr<Pacer<T>> mPacer;
+  const TimeDuration mInterval;
+};
+
+class PacerTestInt : public PacerTest<int>, public ::testing::Test {
+ protected:
+  explicit PacerTestInt(TimeDuration aDuplicationInterval)
+      : PacerTest<int>(aDuplicationInterval) {}
+
+  void TearDown() override { PacerTest::TearDown(); }
+};
+
+class PacerTestIntLongDuplication : public PacerTestInt {
+ protected:
+  PacerTestIntLongDuplication() : PacerTestInt(TimeDuration::FromSeconds(10)) {}
+};
+
+class PacerTestIntTenMsDuplication : public PacerTestInt {
+ protected:
+  PacerTestIntTenMsDuplication()
+      : PacerTestInt(TimeDuration::FromMilliseconds(10)) {}
+};
+
+TEST_F(PacerTestIntLongDuplication, Single) {
+  auto now = TimeStamp::Now();
+  auto d1 = TimeDuration::FromMilliseconds(100);
+  EnqueueSoon(1, now + d1);
+
+  auto [i, time] = WaitFor(TakeN(mPacer->PacedItemEvent(), 1)).unwrap()[0];
+  EXPECT_GE(TimeStamp::Now() - now, d1);
+  EXPECT_EQ(i, 1);
+  EXPECT_EQ(time - now, d1);
+}
+
+TEST_F(PacerTestIntLongDuplication, Past) {
+  auto now = TimeStamp::Now();
+  auto d1 = TimeDuration::FromMilliseconds(100);
+  EnqueueSoon(1, now - d1);
+
+  auto [i, time] = WaitFor(TakeN(mPacer->PacedItemEvent(), 1)).unwrap()[0];
+  EXPECT_GE(TimeStamp::Now() - now, -d1);
+  EXPECT_EQ(i, 1);
+  EXPECT_EQ(time - now, -d1);
+}
+
+TEST_F(PacerTestIntLongDuplication, TimeReset) {
+  auto now = TimeStamp::Now();
+  auto d1 = TimeDuration::FromMilliseconds(100);
+  auto d2 = TimeDuration::FromMilliseconds(200);
+  auto d3 = TimeDuration::FromMilliseconds(300);
+  EnqueueSoon(1, now + d1);
+  EnqueueSoon(2, now + d3);
+  EnqueueSoon(3, now + d2);
+
+  auto items = WaitFor(TakeN(mPacer->PacedItemEvent(), 2)).unwrap();
+
+  {
+    auto [i, time] = items[0];
+    EXPECT_GE(TimeStamp::Now() - now, d1);
+    EXPECT_EQ(i, 1);
+    EXPECT_EQ(time - now, d1);
+  }
+  {
+    auto [i, time] = items[1];
+    EXPECT_GE(TimeStamp::Now() - now, d2);
+    EXPECT_EQ(i, 3);
+    EXPECT_EQ(time - now, d2);
+  }
+}
+
+TEST_F(PacerTestIntTenMsDuplication, SingleDuplication) {
+  auto now = TimeStamp::Now();
+  auto d1 = TimeDuration::FromMilliseconds(100);
+  EnqueueSoon(1, now + d1);
+
+  auto items = WaitFor(TakeN(mPacer->PacedItemEvent(), 2)).unwrap();
+
+  {
+    auto [i, time] = items[0];
+    EXPECT_GE(TimeStamp::Now() - now, d1);
+    EXPECT_EQ(i, 1);
+    EXPECT_EQ(time - now, d1);
+  }
+  {
+    auto [i, time] = items[1];
+    EXPECT_GE(TimeStamp::Now() - now, d1 + mInterval);
+    EXPECT_EQ(i, 1);
+    EXPECT_EQ(time - now, d1 + mInterval);
+  }
+}
+
+TEST_F(PacerTestIntTenMsDuplication, RacyDuplication1) {
+  auto now = TimeStamp::Now();
+  auto d1 = TimeDuration::FromMilliseconds(100);
+  auto d2 = d1 + mInterval - TimeDuration::FromMicroseconds(1);
+  EnqueueSoon(1, now + d1);
+  EnqueueSoon(2, now + d2);
+
+  auto items = WaitFor(TakeN(mPacer->PacedItemEvent(), 3)).unwrap();
+
+  {
+    auto [i, time] = items[0];
+    EXPECT_GE(TimeStamp::Now() - now, d1);
+    EXPECT_EQ(i, 1);
+    EXPECT_EQ(time - now, d1);
+  }
+  {
+    auto [i, time] = items[1];
+    EXPECT_GE(TimeStamp::Now() - now, d2);
+    EXPECT_EQ(i, 2);
+    EXPECT_EQ(time - now, d2);
+  }
+  {
+    auto [i, time] = items[2];
+    EXPECT_GE(TimeStamp::Now() - now, d2 + mInterval);
+    EXPECT_EQ(i, 2);
+    EXPECT_EQ(time - now, d2 + mInterval);
+  }
+}
+
+TEST_F(PacerTestIntTenMsDuplication, RacyDuplication2) {
+  auto now = TimeStamp::Now();
+  auto d1 = TimeDuration::FromMilliseconds(100);
+  auto d2 = d1 + mInterval + TimeDuration::FromMicroseconds(1);
+  EnqueueSoon(1, now + d1);
+  EnqueueSoon(2, now + d2);
+
+  auto items = WaitFor(TakeN(mPacer->PacedItemEvent(), 3)).unwrap();
+
+  {
+    auto [i, time] = items[0];
+    EXPECT_GE(TimeStamp::Now() - now, d1);
+    EXPECT_EQ(i, 1);
+    EXPECT_EQ(time - now, d1);
+  }
+  {
+    auto [i, time] = items[1];
+    EXPECT_GE(TimeStamp::Now() - now, d1 + mInterval);
+    EXPECT_EQ(i, 1);
+    EXPECT_EQ(time - now, d1 + mInterval);
+  }
+  {
+    auto [i, time] = items[2];
+    EXPECT_GE(TimeStamp::Now() - now, d2);
+    EXPECT_EQ(i, 2);
+    EXPECT_EQ(time - now, d2);
+  }
+}