Scroll-bar browser test.

remoting/webapp/browser_test/scrollbar_browser_test.js

+// Copyright 2014 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.
+
+/**
+ * @suppress {checkTypes}
+ *
+ * @fileoverview
+ * Browser test for the scenario below:
+ * 1. Resize the client window to various sizes and verify the existence of
+ *    horizontal and/or vertical scroll-bars.
+ * 2. TODO(jamiewalch): Connect to a host and toggle various combinations of
+ *    scale and resize; repeat test 1.
+ * 3. TODO(jamiewalch): Disconnect; repeat test 1.
+ */
+
+'use strict';
+
+/** @constructor */
+browserTest.Scrollbars = function() {
+  this.scroller_ = document.getElementById('scroller');
+  this.SCROLLBAR_WIDTH_ = 16;
+  this.BORDER_WIDTH_ = 1;
+
+  // The top border is already accounted for by getBoundingClientRect, but
+  // the bottom border is not.
+  var marker = document.getElementById('bottom-marker');
+  this.CONTENT_HEIGHT_ =
+      marker.getBoundingClientRect().top + this.BORDER_WIDTH_;
+
+  // The width of the content is computed from the width of a <section> (690px)
+  // plus the margin of the "inset" class (20px). There's no easy way to get
+  // that without hard-coding it. In fact, this is a bit simplistic because
+  // the horizontal space required by the header depends on the length of the
+  // product name.
+  this.CONTENT_WIDTH_ = 690 + 20 + 2 * this.BORDER_WIDTH_;
+
+};
+
+
+browserTest.Scrollbars.prototype.run = function(data) {
+  if (!base.isAppsV2()) {
+    browserTest.fail(
+        'Scroll-bar testing requires resizing the app window, which can ' +
+        'only be done programmatically in apps v2.');
+  }
+
+  // Verify that scrollbars are added/removed correctly on the home screen.
+  this.verifyHomeScreenScrollbars_()
+      .then(browserTest.pass, browserTest.fail);
+};
+
+
+/**
+ * Verify the test cases for the home-screen.
+ */
+browserTest.Scrollbars.prototype.verifyHomeScreenScrollbars_ = function() {
+  // Note that, due to crbug.com/240772, if the window already has
+  // scroll-bars, they will not be removed if the window size is
+  // increased by less than the scroll-bar width. We work around that
+  // when connected to a host because we know how big the content is
+  // (in fact, testing this work-around is the main motivation for
+  // writing this test), but it's not worth it for the home screen,
+  // so make the window large not to require scrollbars before each test.
+  var tooWide = this.CONTENT_WIDTH_ + 100;
+  var tooTall = this.CONTENT_HEIGHT_ + 100;
+  var removeScrollbars = this.resize_.bind(this, tooWide, tooTall);
+
+  // Verify there are no scroll-bars if the window is as big as it needs
+  // to be.
+  return removeScrollbars()
+  .then(this.resizeAndVerifyScroll_(
+        this.CONTENT_WIDTH_,
+        this.CONTENT_HEIGHT_,
+        false, false))
+
+  // Verify there is a vertical scroll-bar if the window is shorter than it
+  // needs to be.
+  .then(removeScrollbars)
+  .then(this.resizeAndVerifyScroll_.bind(
+        this,
+        this.CONTENT_WIDTH_ + this.SCROLLBAR_WIDTH_,
+        this.CONTENT_HEIGHT_ - 1,
+        false, true))
+
+  // Verify there is a horizontal scroll-bar if the window is narrow than it
+  // needs to be.
+  .then(removeScrollbars)
+  .then(this.resizeAndVerifyScroll_.bind(
+        this,
+        this.CONTENT_WIDTH_ - 1,
+        this.CONTENT_HEIGHT_ + this.SCROLLBAR_WIDTH_,
+        true, false))
+
+  // Verify there are both horizontal and vertical scroll-bars, even if one
+  // is only needed as a result of the space occupied by the other.
+  .then(removeScrollbars)
+  .then(this.resizeAndVerifyScroll_.bind(
+        this,
+        this.CONTENT_WIDTH_,
+        this.CONTENT_HEIGHT_ - 1,
+        true, true))
+  .then(removeScrollbars)
+  .then(this.resizeAndVerifyScroll_.bind(
+        this,
+        this.CONTENT_WIDTH_ - 1,
+        this.CONTENT_HEIGHT_,
+        true, true))
+
+  // Verify there are both horizontal and vertical scroll-bars, if both are
+  // required independently.
+  .then(removeScrollbars)
+  .then(this.resizeAndVerifyScroll_.bind(
+        this,
+        this.CONTENT_WIDTH_ - 1,
+        this.CONTENT_HEIGHT_ - 1,
+        true, true));
+};
+
+
+/**
+ * Returns whether or not horizontal and vertical scroll-bars are expected
+ * and visible. To do this, it performs a hit-test close to the right and
+ * bottom edges of the scroller <div>; since the content of that <div> fills
+ * it completely, the hit-test will return the content unless there is a
+ * scroll-bar visible on the corresponding edge, in which case it will return
+ * the scroller <div> itself.
+ *
+ * @private
+ */
+browserTest.Scrollbars.prototype.getScrollbarState_ = function() {
+  var rect = this.scroller_.getBoundingClientRect();
+  var rightElement = document.elementFromPoint(
+      rect.right - 1, (rect.top + rect.bottom) / 2);
+  var bottomElement = document.elementFromPoint(
+      (rect.left + rect.right) / 2, rect.bottom - 1);
+  return {
+    horizontal: bottomElement === this.scroller_,
+    vertical: rightElement === this.scroller_
+  };
+};
+
+
+/**
+ * Returns a promise that resolves if the scroll-bar state is as expected, or
+ * rejects otherwise.
+ *
+ * @private
+ */
+browserTest.Scrollbars.prototype.verifyScrollbarState_ =
+    function(horizontalExpected, verticalExpected) {
+  var scrollbarState = this.getScrollbarState_();
+  if (scrollbarState.horizontal && !horizontalExpected) {
+    return Promise.reject(new Error(
+        'Horizontal scrollbar present but not expected.'));
+  } else if (!scrollbarState.horizontal && horizontalExpected) {
+    return Promise.reject(new Error(
+        'Horizontal scrollbar expected but not present.'));
+  } else if (scrollbarState.vertical && !verticalExpected) {
+    return Promise.reject(new Error(
+        'Vertical scrollbar present but not expected.'));
+  } else if (!scrollbarState.vertical && verticalExpected) {
+    return Promise.reject(new Error(
+        'Vertical scrollbar expected but not present.'));
+  }
+  return Promise.resolve();
+};
+
+
+/**
+ * @private
+ * @return {Promise} A promise that will be fulfilled when the window has
+ *     been resized and it's safe to test scroll-bar visibility.
+ */
+browserTest.Scrollbars.prototype.resize_ = function(width, height) {
+  var win = chrome.app.window.current();
+  win.resizeTo(width, height);
+  // Chrome takes a while to update the scroll-bars, so don't resolve
+  // immediately. Waiting for the onBoundsChanged event would be cleaner,
+  // but isn't reliable.
+  return base.Promise.sleep(500);
+};
+
+
+/**
+ * @private
+ * @return {Promise} A promise that will be fulfilled when the window has
+ *     been resized and it's safe to test scroll-bar visibility.
+ */
+browserTest.Scrollbars.prototype.resizeAndVerifyScroll_ =
+    function(width, height, horizontalExpected, verticalExpected) {
+  return this.resize_(width, height).then(
+      this.verifyScrollbarState_.bind(
+          this, horizontalExpected, verticalExpected));
+};