Add FrameGenerator Unit Tests

services/ui/ws/frame_generator_unittest.cc

Index: services/ui/ws/frame_generator_unittest.cc
diff --git a/services/ui/ws/frame_generator_unittest.cc b/services/ui/ws/frame_generator_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..6b7d7736d4a98c58121aa89eb2d7bb2e338253f7
--- /dev/null
+++ b/services/ui/ws/frame_generator_unittest.cc
@@ -0,0 +1,159 @@
+// 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/begin_frame_args_test.cc"
+#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 "services/ui/ws/server_window_delegate.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; }
+};
+
+class TestServerWindowDelegate : public ServerWindowDelegate {
+ public:
+  TestServerWindowDelegate() {}
+  ~TestServerWindowDelegate() override {}
+
+  // ServerWindowDelegate implementation:
+  cc::mojom::DisplayCompositor* GetDisplayCompositor() override {
+    return nullptr;
+  }
+
+  ServerWindow* GetRootWindow(const ServerWindow* window) override {
+    return nullptr;
+  }
+};
+
+// FakeCompositorFrameSink observes a FakeExternalBeginFrameSource and receives
+// CompositorFrame from a FrameGenerator.
+class FakeCompositorFrameSink : public cc::CompositorFrameSink,
+                                public cc::BeginFrameObserver,
+                                public cc::ExternalBeginFrameSourceClient {
+ public:
+  FakeCompositorFrameSink()
+      : cc::CompositorFrameSink(nullptr, nullptr, nullptr, nullptr) {}
+
+  // cc::CompositorFrameSink implementation:
+  bool BindToClient(cc::CompositorFrameSinkClient* client) override {
+    if (!cc::CompositorFrameSink::BindToClient(client))
+      return false;
+
+    begin_frame_source_ = base::MakeUnique<cc::ExternalBeginFrameSource>(this);
+    client_->SetBeginFrameSource(begin_frame_source_.get());
+    return true;
+  }
+
+  void DetachFromClient() override {
+    cc::CompositorFrameSink::DetachFromClient();
+  }
+
+  void SubmitCompositorFrame(cc::CompositorFrame frame) override {
+    ++number_frames_received_;
+  }
+
+  // cc::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 {}
+
+  // cc::ExternalBeginFrameSourceClient implementation:
+  void OnNeedsBeginFrames(bool needs_begin_frames) override {}
+
+  void OnDidFinishFrame(const cc::BeginFrameAck& ack) 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 {}
+
+  // testing::Test overrides:
+  void SetUp() override {
+    testing::Test::SetUp();
+
+    std::unique_ptr<FakeCompositorFrameSink> compositor_frame_sink =
+        base::MakeUnique<FakeCompositorFrameSink>();
+    compositor_frame_sink_ = compositor_frame_sink.get();
+
+    constexpr float kRefreshRate = 0.f;
+    constexpr bool kTickAutomatically = false;
+    begin_frame_source_ = base::MakeUnique<cc::FakeExternalBeginFrameSource>(
+        kRefreshRate, kTickAutomatically);
+    begin_frame_source_->AddObserver(compositor_frame_sink_);
+    delegate_ = base::MakeUnique<TestFrameGeneratorDelegate>();
+    server_window_delegate_ = base::MakeUnique<TestServerWindowDelegate>();
+    root_window_ = base::MakeUnique<ServerWindow>(server_window_delegate_.get(),
+                                                  WindowId());
+    root_window_->SetVisible(true);
+    frame_generator_ = base::MakeUnique<FrameGenerator>(
+        delegate_.get(), root_window_.get(), std::move(compositor_frame_sink));
+  };
+
+  void TearDown() override { testing::Test::TearDown(); }
+
+  int NumberOfFramesRecieved() {
+    return compositor_frame_sink_->number_frames_received();
+  }
+
+  void IssueBeginFrame(const cc::BeginFrameArgs& args) {
+    begin_frame_source_->TestOnBeginFrame(args);
+  }
+
+ private:
+  FakeCompositorFrameSink* compositor_frame_sink_ = nullptr;
+  std::unique_ptr<cc::FakeExternalBeginFrameSource> begin_frame_source_;
+  std::unique_ptr<TestFrameGeneratorDelegate> delegate_;
+  std::unique_ptr<TestServerWindowDelegate> server_window_delegate_;
+  std::unique_ptr<ServerWindow> root_window_;
+  std::unique_ptr<FrameGenerator> frame_generator_;
+
+  DISALLOW_COPY_AND_ASSIGN(FrameGeneratorTest);
+};
+
+TEST_F(FrameGeneratorTest, Creation) {
+  DCHECK_EQ(0, NumberOfFramesRecieved());
+
+  // FrameGenerator does not request BeginFrames upon creation.
+  cc::BeginFrameArgs args =
+      cc::CreateBeginFrameArgsForTesting(BEGINFRAME_FROM_HERE, 0, 1);
+  IssueBeginFrame(args);
+  EXPECT_EQ(0, NumberOfFramesRecieved());

[Fady Samuel, 2017/03/15 17:47:00]

I'd like to see this do a bit more:

EXPECT_EQ(0, NumberOfFramesRecieved());

// FrameGenerator does not request BeginFrames upon creation.
IssueBeginFrame(...);
EXPECT_EQ(0, NumberOfFramesRecieved());

frame_generator()->OnSurfaceCreated(cc::SurfaceInfo(MakeSurfaceId(), SomeSize,
SomeDeviceScaleFactor));
EXPECT_EQ(0, NumberOfFramesRecieved());

// Changing the window manager's surface ID should trigger the creation
// of a new CompositorFrame from FrameGenerator.
IssueBeginFrame(...);
EXPECT_EQ(1, NumberOfFramesRecieved());

// Might be useful inspecting the content of the frame here.

[Alex Z., 2017/03/15 20:37:12]

Done.

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