<!DOCTYPE html>
<!--
Copyright (c) 2015 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.
-->

<link rel="import" href="/tracing/base/task.html">
<link rel="import" href="/tracing/ui/base/resize_sensor.html">

<script>
'use strict';

tr.b.unittest.testSuite(function() {
  function forceLayout(element) {
    element.offsetHeight;
  }

  test('instantiate', function() {
    var sensor = document.createElement('tr-ui-b-resize-sensor');
    sensor.appendChild(document.createTextNode('hello'));

    var resizeCount = 0;
    function onResize(event) {
      resizeCount += 1;
    }

    this.addHTMLOutput(sensor);
    forceLayout(sensor);
    sensor.addEventListener('resize', onResize);

    // Trigger a resize:
    sensor.style.fontSize = '20pt';
    forceLayout(sensor);

    // The event doesn't fire synchronously, so return a Promise that will
    // resolve whenever the test is done.
    return new Promise(function(resolve, reject) {
      // The resize event fires when the sensor is re-laid-out.
      // Use requestAnimationFrame to wait until after the sensor is
      // re-laid-out.
      // This doesn't work if the page becomes invisible.
      window.requestAnimationFrame(function() {
        assert.equal(1, resizeCount);
        sensor.removeEventListener('resize', onResize);
        sensor.style.fontSize = '12pt';
        forceLayout(sensor);
        window.requestAnimationFrame(function() {
          assert.equal(1, resizeCount);
          resolve();
        });
      });
    });
  });
});
</script>