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 "platform/testing/UnitTestHelpers.h"
#include "web/WebViewImpl.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"
#include "wtf/CurrentTime.h"

namespace blink {

namespace {

class TestIntersectionObserverCallback : public IntersectionObserverCallback {
 public:
  TestIntersectionObserverCallback(Document& document)
      : m_document(document), m_callCount(0) {}
  void handleEvent(const HeapVector<Member<IntersectionObserverEntry>>&,
                   IntersectionObserver&) override {
    m_callCount++;
  }
  ExecutionContext* getExecutionContext() const override { return m_document; }
  int callCount() const { return m_callCount; }

  DEFINE_INLINE_TRACE() {
    IntersectionObserverCallback::trace(visitor);
    visitor->trace(m_document);
  }

 private:
  Member<Document> m_document;
  int m_callCount;
};

}  // namespace

class IntersectionObserverTest : public SimTest {};

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

  IntersectionObserverInit observerInit;
  TrackExceptionState exceptionState;
  TestIntersectionObserverCallback* observerCallback =
      new TestIntersectionObserverCallback(document());
  IntersectionObserver* observer = IntersectionObserver::create(
      observerInit, *observerCallback, exceptionState);
  ASSERT_FALSE(exceptionState.hadException());

  compositor().beginFrame();
  ASSERT_FALSE(compositor().needsBeginFrame());
  EXPECT_TRUE(observer->takeRecords(exceptionState).isEmpty());
  EXPECT_EQ(observerCallback->callCount(), 0);

  Element* target = document().getElementById("target");
  ASSERT_TRUE(target);
  observer->observe(target, exceptionState);
  EXPECT_TRUE(compositor().needsBeginFrame());
}

}  // namespace blink