feat: Add a new instruction focus to focus an element

Author: prantlf

Gruntfile.js

@@ -319,13 +319,24 @@ module.exports = function (grunt) {
               value: '<div class="class" tabindex="0">Text</div>'
             }
           },
+          coverage ? { wait: 1 } : {
+            focus: 'body',
+            wait: function (browser) {
+              return browser.hasFocus('body')
+                .then(function (value) {
+                  if (value !== false) {
+                    throw new Error('focus on body failed')
+                  }
+                })
+            }
+          },
           {
-            clickIfVisible: 'select',
+            clickIfVisible: 'input',
             wait: function (browser) {
-              return browser.hasFocus('select')
+              return browser.hasFocus('input')
                 .then(function (value) {
-                  if (value === false) {
-                    throw new Error('clickIfVisible on select failed')
+                  if (value !== false) {
+                    throw new Error('clickIfVisible on invisible input failed')
                   }
                 })
             }

tasks/html-dom-snapshot.js

@@ -8,10 +8,10 @@ const mkdirp = require('mkdirp')
 // order in a command object. In this order they will be looked for and
 // executed.
 const instructionKeys = [
-  'setViewport', 'url', 'go', 'scroll', 'clearValue', 'setValue', 'addValue',
-  'selectOptionByIndex', 'selectOptionByValue', 'moveCursor',
-  'click', 'clickIfVisible', 'keys', 'wait', 'hasAttribute', 'hasClass', 'hasValue',
-  'hasText', 'hasInnerHtml', 'hasOuterHtml',
+  'setViewport', 'url', 'go', 'scroll', 'focus', 'clearValue', 'setValue',
+  'addValue', 'selectOptionByIndex', 'selectOptionByValue', 'moveCursor',
+  'click', 'clickIfVisible', 'keys', 'wait', 'hasAttribute', 'hasClass',
+  'hasValue', 'hasText', 'hasInnerHtml', 'hasOuterHtml',
   'isEnabled', 'isExisting', 'isFocused', 'isSelected', 'isVisible',
   'isVisibleWithinViewport', 'isNotEnabled', 'isNotExisting',
   'isNotFocused', 'isNotSelected', 'isNotVisible',

tasks/instructions/focus.js

@@ -0,0 +1,30 @@
+'use strict'
+
+// Istanbul instruments the callback to be executed in the browser,
+// introduces variables there, which are defined only in the node
+// part of the code and thus breaks the code.
+
+/* istanbul ignore next */
+
+module.exports = {
+  detect: function (command) {
+    return !!command.focus
+  },
+
+  perform: function (grunt, target, client, command) {
+    const focus = command.focus
+    grunt.verbose.writeln('Focus "' + focus + '".')
+    return client.execute(function (selector) {
+      var element = document.querySelector(selector)
+      if (!element) {
+        return false
+      }
+      element.focus()
+    }, focus)
+    .then(function (value) {
+      if (value === false) {
+        throw new Error('"' + focus + '" does not exist.')
+      }
+    })
+  }
+}