tests: refactor some frontend tests (#4408)

* don't include sendkeys in index.html as it's included in helper.init
mocha opts: add default timeout and replace ignoreLeaks with checkLeaks,
as the former is deprecated

* introduce helper.edit to write to a pad

* add test to check if helper.edit() supports line numbers

* helper tests: waitFor/waitForPromise seem to be a little bit faster sometimes

* tests: refactor chat.js

* tests: refactor timeslider_numeric_padID

* tests: refactor timeslider_labels

* tests: refactor timeslider_follow

* ensure followContents is enabled, although it should be by default

* timeslider_follow: increase number of revision for Edge

* make textLines() depend on linesDiv()

Co-authored-by: Richard Hansen <rhansen@rhansen.org>

* make linesDiv return standard Array

* use `contain` instead of `indexOf`

* more fixes from the review

* review fixes

* align waitFor and waitForPromise behaviour

* timeslider_follow: check if it's following to the correct lines

* lower expected waitFor/waitForPromise interval check

* disable responsivness and regression test in timeslider_follow

* timeslider_follow: fix Range detection

* more explicit test for linesDiv

Co-authored-by: Richard Hansen <rhansen@rhansen.org>

tests/frontend/helper/ui.js

@@ -0,0 +1,146 @@
+/**
+ * the contentWindow is either the normal pad or timeslider
+ *
+ * @returns {HTMLElement} contentWindow
+ */
+helper.contentWindow = function(){
+  return $('#iframe-container iframe')[0].contentWindow;
+}
+
+/**
+ * Opens the chat unless it is already open via an
+ * icon on the bottom right of the page
+ *
+ * @returns {Promise}
+ */
+helper.showChat = function(){
+  var chaticon = helper.chatIcon();
+  if(chaticon.hasClass('visible')) {
+    chaticon.click()
+    return helper.waitForPromise(function(){return !chaticon.hasClass('visible'); },2000)
+  }
+}
+
+/**
+ * Closes the chat window if it is shown and not sticky
+ *
+ * @returns {Promise}
+ */
+helper.hideChat = function(){
+  if(helper.isChatboxShown() && !helper.isChatboxSticky()) {
+    helper.titlecross().click()
+    return helper.waitForPromise(function(){return !helper.isChatboxShown(); },2000);
+  }
+}
+
+/**
+ * Gets the chat icon from the bottom right of the page
+ *
+ * @returns {HTMLElement} the chat icon
+ */
+helper.chatIcon = function(){return helper.padChrome$('#chaticon')}
+
+/**
+ * The chat messages from the UI
+ *
+ * @returns {Array.<HTMLElement>}
+ */
+helper.chatTextParagraphs = function(){return helper.padChrome$('#chattext').children("p")}
+
+/**
+ * Returns true if the chat box is sticky
+ *
+ * @returns {boolean} stickyness of the chat box
+ */
+helper.isChatboxSticky = function() {
+  return helper.padChrome$('#chatbox').hasClass('stickyChat');
+}
+
+/**
+ * Returns true if the chat box is shown
+ *
+ * @returns {boolean} visibility of the chat box
+ */
+helper.isChatboxShown = function() {
+  return helper.padChrome$('#chatbox').hasClass('visible');
+}
+
+/**
+ * Gets the settings menu
+ *
+ * @returns {HTMLElement} the settings menu
+ */
+helper.settingsMenu = function(){return helper.padChrome$('#settings') };
+
+/**
+ * Gets the settings button
+ *
+ * @returns {HTMLElement} the settings button
+ */
+helper.settingsButton = function(){return helper.padChrome$("button[data-l10n-id='pad.toolbar.settings.title']") }
+
+/**
+ * Gets the titlecross icon
+ *
+ * @returns {HTMLElement} the titlecross icon
+ */
+helper.titlecross = function(){return helper.padChrome$('#titlecross')}
+
+/**
+ * Returns true if the settings menu is visible
+ *
+ * @returns {boolean} is the settings menu shown?
+ */
+helper.isSettingsShown = function() {
+  return helper.padChrome$('#settings').hasClass('popup-show');
+}
+
+/**
+ * Gets the timer div of a timeslider that has the datetime of the revision
+ *
+ * @returns {HTMLElement} timer
+ */
+helper.timesliderTimer = function(){
+  if(typeof helper.contentWindow().$ == 'function'){
+    return helper.contentWindow().$('#timer') }
+  }
+
+/**
+ * Gets the time of the revision on a timeslider
+ *
+ * @returns {HTMLElement} timer
+ */
+helper.timesliderTimerTime = function(){
+  if(helper.timesliderTimer()){
+    return helper.timesliderTimer().text()
+  }
+}
+
+/**
+ * The ui-slidar-bar element in the timeslider
+ *
+ * @returns {HTMLElement}
+ */
+helper.sliderBar = function(){
+  return helper.contentWindow().$('#ui-slider-bar')
+}
+
+/**
+ * revision_date element
+ * like "Saved October 10, 2020"
+ *
+ * @returns {HTMLElement}
+ */
+helper.revisionDateElem = function(){
+  return helper.contentWindow().$('#revision_date').text();
+}
+
+/**
+ * revision_label element
+ * like "Version 1"
+ *
+ * @returns {HTMLElement}
+ */
+helper.revisionLabelElem = function(){
+  return helper.contentWindow().$('#revision_label')
+}