Add FrameGenerator Unit Tests

services/ui/ws/frame_generator_unittest.cc

+// Copyright 2017 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 "services/ui/ws/frame_generator.h"
+
+#include "base/macros.h"
+#include "cc/output/compositor_frame_sink.h"
+#include "cc/scheduler/begin_frame_source.h"
+#include "cc/test/fake_external_begin_frame_source.h"
+#include "services/ui/ws/frame_generator_delegate.h"
+#include "services/ui/ws/server_window.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace ui {
+namespace ws {
+namespace test {
+
+class TestFrameGeneratorDelegate : public FrameGeneratorDelegate {
+ public:
+  TestFrameGeneratorDelegate() {}
+  ~TestFrameGeneratorDelegate() override {}
+
+  // FrameGeneratorDelegate implementation:
+  bool IsInHighContrastMode() override { return false; }
+};
+
+// FakeCompositorFrameSink observes a FakeExternalBeginFrameSource and receives
+// CompositorFrame from a FrameGenerator.
+class FakeCompositorFrameSink : public cc::CompositorFrameSink,
+                                public cc::BeginFrameObserver {
+ public:
+  FakeCompositorFrameSink()
+      : cc::CompositorFrameSink(nullptr, nullptr, nullptr, nullptr) {}
+
+  // cc::CompositorFrameSink implementation:
+  bool BindToClient(cc::CompositorFrameSinkClient* client) override {
+    if (!cc::CompositorFrameSink::BindToClient(client))
+      return false;
+
+    return true;
+  }
+
+  void DetachFromClient() override {
+    cc::CompositorFrameSink::DetachFromClient();
+  }
+
+  void SubmitCompositorFrame(cc::CompositorFrame frame) override {
+    ++number_frames_received_;
+  }
+
+  // BeginFrameObserver implementation.
+  void OnBeginFrame(const cc::BeginFrameArgs& args) override {
+    begin_frame_source_->OnBeginFrame(args);
+    last_begin_frame_args_ = args;
+  }
+
+  const cc::BeginFrameArgs& LastUsedBeginFrameArgs() const override {
+    return last_begin_frame_args_;
+  }
+
+  void OnBeginFrameSourcePausedChanged(bool paused) override {}
+
+  int number_frames_received() { return number_frames_received_; }
+
+ private:
+  int number_frames_received_ = 0;
+  std::unique_ptr<cc::ExternalBeginFrameSource> begin_frame_source_;
+  cc::BeginFrameArgs last_begin_frame_args_;
+};
+
+class FrameGeneratorTest : public testing::Test {
+ public:
+  FrameGeneratorTest() {}
+  ~FrameGeneratorTest() override {}
+
+ protected:
+ private:
+  DISALLOW_COPY_AND_ASSIGN(FrameGeneratorTest);
+};
+
+TEST_F(FrameGeneratorTest, Creation) {
+  // Create a FrameGenerator-FakeCompositorFrameSink pair
+  // Tick FakeExternalBeginFrameSouce and verified if FakeCompositorFrameSink
+  // receives a CompositorFrameSink based on FrameGenerator's state.
+  constexpr float refresh_rate = 0.f;
+  constexpr bool tick_automatically = false;
+  const cc::BeginFrameArgs kArgs;
+
+  // TODO(staraz): Put some of this in SetUp()
+  std::unique_ptr<FakeCompositorFrameSink> compositor_frame_sink =
+      base::MakeUnique<FakeCompositorFrameSink>();
+  cc::FakeExternalBeginFrameSource begin_frame_source(refresh_rate,
+                                                      tick_automatically);
+  begin_frame_source.AddObserver(compositor_frame_sink.get());
+  TestFrameGeneratorDelegate delegate;
+  ServerWindow root_window(nullptr, WindowId());
+  root_window.SetVisible(true);
+  FrameGenerator frame_generator(&delegate, &root_window,
+                                 std::move(compositor_frame_sink));

[Fady Samuel, 2017/03/15 00:06:07]

I would move most of the above to a FrameGeneratorTest::SetUp given that all
unit tests will deal with FrameGenerator.

[Alex Z., 2017/03/15 17:40:00]

Done.

+  EXPECT_EQ(0, compositor_frame_sink->number_frames_received());
+
+  // FrameGenerator does not request BeginFrames upon creation.
+  begin_frame_source.TestOnBeginFrame(kArgs);

[Fady Samuel, 2017/03/15 00:06:07]

Make this a public method "IssueBeginFrame" on FrameGeneratorTest.

[Alex Z., 2017/03/15 17:40:00]

Done.

+  EXPECT_EQ(0, compositor_frame_sink->number_frames_received());
+}

[Fady Samuel, 2017/03/15 00:06:07]

This unit test can probably collapse to look like this once you move things into
FrameGeneratorTest:

TEST_F(FrameGeneratorTest, Creation) {
  EXPECT_EQ(0, compositor_frame_sink()->number_frames_received());
  IssueBeginFrame();
  EXPECT_EQ(0, compositor_frame_sink()->number_frames_received());
}

[Alex Z., 2017/03/15 17:40:01]

Done.

+
+// TODO(staraz): Add OnSurfaceCreated test and SetDeviceScaleFactor test.
+
+}  // namespace test
+}  // namespace ws
+}  // namespace ui