third_party/WebKit/Source/web/tests/IntersectionObserverTest.cpp

// Copyright 2016 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 "core/dom/IntersectionObserver.h"

#include "core/dom/IntersectionObserverCallback.h"
#include "core/dom/IntersectionObserverInit.h"
#include "core/exported/WebViewBase.h"
#include "core/frame/FrameView.h"
#include "platform/testing/UnitTestHelpers.h"
#include "platform/wtf/CurrentTime.h"
#include "web/tests/sim/SimCompositor.h"
#include "web/tests/sim/SimDisplayItemList.h"
#include "web/tests/sim/SimRequest.h"
#include "web/tests/sim/SimTest.h"

namespace blink {

namespace {

class TestIntersectionObserverCallback : public IntersectionObserverCallback {
 public:
  TestIntersectionObserverCallback(Document& document)
      : document_(document), call_count_(0) {}
  void HandleEvent(const HeapVector<Member<IntersectionObserverEntry>>&,
                   IntersectionObserver&) override {
    call_count_++;
  }
  ExecutionContext* GetExecutionContext() const override { return document_; }
  int CallCount() const { return call_count_; }

  DEFINE_INLINE_TRACE() {
    IntersectionObserverCallback::Trace(visitor);
    visitor->Trace(document_);
  }

 private:
  Member<Document> document_;
  int call_count_;
};

}  // namespace

class IntersectionObserverTest : public SimTest {};

TEST_F(IntersectionObserverTest, ObserveSchedulesFrame) {
  SimRequest main_resource("https://example.com/", "text/html");
  LoadURL("https://example.com/");
  main_resource.Complete("<div id='target'></div>");

  IntersectionObserverInit observer_init;
  DummyExceptionStateForTesting exception_state;
  TestIntersectionObserverCallback* observer_callback =
      new TestIntersectionObserverCallback(GetDocument());
  IntersectionObserver* observer = IntersectionObserver::Create(
      observer_init, *observer_callback, exception_state);
  ASSERT_FALSE(exception_state.HadException());

  Compositor().BeginFrame();
  ASSERT_FALSE(Compositor().NeedsBeginFrame());
  EXPECT_TRUE(observer->takeRecords(exception_state).IsEmpty());
  EXPECT_EQ(observer_callback->CallCount(), 0);

  Element* target = GetDocument().getElementById("target");
  ASSERT_TRUE(target);
  observer->observe(target, exception_state);
  EXPECT_TRUE(Compositor().NeedsBeginFrame());
}

TEST_F(IntersectionObserverTest, ResumePostsTask) {
  WebView().Resize(WebSize(800, 600));
  SimRequest main_resource("https://example.com/", "text/html");
  LoadURL("https://example.com/");
  main_resource.Complete(
      "<div id='leading-space' style='height: 700px;'></div>"
      "<div id='target'></div>"
      "<div id='trailing-space' style='height: 700px;'></div>");

  IntersectionObserverInit observer_init;
  DummyExceptionStateForTesting exception_state;
  TestIntersectionObserverCallback* observer_callback =
      new TestIntersectionObserverCallback(GetDocument());
  IntersectionObserver* observer = IntersectionObserver::Create(
      observer_init, *observer_callback, exception_state);
  ASSERT_FALSE(exception_state.HadException());

  Element* target = GetDocument().getElementById("target");
  ASSERT_TRUE(target);
  observer->observe(target, exception_state);

  Compositor().BeginFrame();
  testing::RunPendingTasks();
  EXPECT_EQ(observer_callback->CallCount(), 1);

  // When document is not suspended, beginFrame() will generate notifications
  // and post a task to deliver them.
  GetDocument().View()->LayoutViewportScrollableArea()->SetScrollOffset(
      ScrollOffset(0, 300), kProgrammaticScroll);
  Compositor().BeginFrame();
  EXPECT_EQ(observer_callback->CallCount(), 1);
  testing::RunPendingTasks();
  EXPECT_EQ(observer_callback->CallCount(), 2);

  // When a document is suspended, beginFrame() will generate a notification,
  // but it will not be delivered.  The notification will, however, be
  // available via takeRecords();
  GetDocument().SuspendScheduledTasks();
  GetDocument().View()->LayoutViewportScrollableArea()->SetScrollOffset(
      ScrollOffset(0, 0), kProgrammaticScroll);
  Compositor().BeginFrame();
  EXPECT_EQ(observer_callback->CallCount(), 2);
  testing::RunPendingTasks();
  EXPECT_EQ(observer_callback->CallCount(), 2);
  EXPECT_FALSE(observer->takeRecords(exception_state).IsEmpty());

  // Generate a notification while document is suspended; then resume document.
  // Notification should happen in a post task.
  GetDocument().View()->LayoutViewportScrollableArea()->SetScrollOffset(
      ScrollOffset(0, 300), kProgrammaticScroll);
  Compositor().BeginFrame();
  testing::RunPendingTasks();
  EXPECT_EQ(observer_callback->CallCount(), 2);
  GetDocument().ResumeScheduledTasks();
  EXPECT_EQ(observer_callback->CallCount(), 2);
  testing::RunPendingTasks();
  EXPECT_EQ(observer_callback->CallCount(), 3);
}

TEST_F(IntersectionObserverTest, DisconnectClearsNotifications) {
  WebView().Resize(WebSize(800, 600));
  SimRequest main_resource("https://example.com/", "text/html");
  LoadURL("https://example.com/");
  main_resource.Complete(
      "<div id='leading-space' style='height: 700px;'></div>"
      "<div id='target'></div>"
      "<div id='trailing-space' style='height: 700px;'></div>");

  IntersectionObserverInit observer_init;
  DummyExceptionStateForTesting exception_state;
  TestIntersectionObserverCallback* observer_callback =
      new TestIntersectionObserverCallback(GetDocument());
  IntersectionObserver* observer = IntersectionObserver::Create(
      observer_init, *observer_callback, exception_state);
  ASSERT_FALSE(exception_state.HadException());

  Element* target = GetDocument().getElementById("target");
  ASSERT_TRUE(target);
  observer->observe(target, exception_state);

  Compositor().BeginFrame();
  testing::RunPendingTasks();
  EXPECT_EQ(observer_callback->CallCount(), 1);

  // If disconnect() is called while an observer has unsent notifications,
  // those notifications should be discarded.
  GetDocument().View()->LayoutViewportScrollableArea()->SetScrollOffset(
      ScrollOffset(0, 300), kProgrammaticScroll);
  Compositor().BeginFrame();
  observer->disconnect();
  testing::RunPendingTasks();
  EXPECT_EQ(observer_callback->CallCount(), 1);
}

}  // namespace blink