feat: Add scroll instruction

Gruntfile.js

@@ -188,6 +188,7 @@ module.exports = function (grunt) {
           },
           {
             url: 'http://localhost:8881/test/pages/input.html',
+            scroll: 'input',
             moveCursor: 'input',
             click: 'input',
             wait: function (browser) {

INSTRUCTIONS.md

@@ -5,6 +5,7 @@ One of the instructions has to be present in every command. These properties are
 - [setViewport](#setviewport)
 - [url](#url)
 - [go](#go)
+- [scroll](#scroll)
 - [clearValue](#clearvalue)
 - [setValue](#setvalue)
 - [addValue](#addvalue)
@@ -76,6 +77,26 @@ Navigates backwards or forwards using the browser history, or refreshes the curr
 }
 ```
 
+## scroll
+Type: `String` | `Object`
+
+Scrolls the page, so that the element with the specified selector or mouse coordinates become visible. If an object is used for the specification, it should contain the following properties:
+
+* `selector` - `String` - selector of the element to move the mose to.
+* `offset` - `Object` - relative offset to the top left corner of the specified element expected as `left` and `top` numeric properties.
+
+```js
+{
+  url: 'https://google.com',
+  scroll: {
+    selector: '#lst-ib'
+  },
+  file: 'google'
+}
+```
+
+The `offset` value can be specified instead of the `selector` and shares the format with the [`moveCursor`](#moveCursor) instruction.
+
 ## clearValue
 Type: `String`
 

README.md

@@ -254,6 +254,7 @@ One of the [instructions] has to be present in every command. These properties a
 * [setViewport](INSTRUCTIONS.md#setviewport)
 * [url](INSTRUCTIONS.md#url)
 * [go](INSTRUCTIONS.md#go)
+* [scroll](INSTRUCTIONS.md#scroll)
 * [clearValue](INSTRUCTIONS.md#clearvalue)
 * [setValue](INSTRUCTIONS.md#setvalue)
 * [addValue](INSTRUCTIONS.md#addvalue)
@@ -508,7 +509,7 @@ your code using Grunt.
 
 ## Release History
 
- * 2018-05-14  [v1.3.0]  Allow saving snapshots to sub-directories, file numbering per-directory
+ * 2018-05-14  [v1.3.0]  Allow saving snapshots to sub-directories, file numbering per-directory, add `scroll` instruction
  * 2018-05-11  [v1.2.0]  Introduce delay after every instruction to be able to visually follow the actions when debugging
  * 2018-03-29  [v1.1.0]  Allow specifying all initialization parameters supported by WebdriverIO
  * 2018-03-28  [v1.0.2]  Stop Selenium and Chromedriver processes on unexpected Grunt process abortion

tasks/html-dom-snapshot.js

@@ -15,7 +15,7 @@ const {basename, dirname, isAbsolute, join} = require('path')
 const mkdirp = require('mkdirp')
 const nodeCleanup = require('node-cleanup')
 const instructions = [
-  'setViewport', 'url', 'go', 'clearValue', 'setValue', 'addValue',
+  'setViewport', 'url', 'go', 'scroll', 'clearValue', 'setValue', 'addValue',
   'selectOptionByIndex', 'selectOptionByValue', 'moveCursor',
   'click', 'keys', 'wait', 'hasAttribute', 'hasClass', 'hasValue',
   'hasText', 'hasInnerHtml', 'hasOuterHtml',

tasks/instructions/scroll.js

@@ -0,0 +1,22 @@
+'use strict'
+
+module.exports = {
+  detect: function (command) {
+    return !!command.scroll
+  },
+
+  perform: function (grunt, target, client, command) {
+    let scroll = command.scroll
+    if (typeof scroll === 'string') {
+      scroll = {selector: scroll}
+    }
+    const selector = scroll.selector
+    if (selector) {
+      grunt.verbose.writeln('Move cursor to "' + selector + '".')
+      return client.scroll(selector)
+    }
+    const offset = scroll.offset || {}
+    grunt.verbose.writeln('Move cursor to ' + JSON.stringify(offset) + '.')
+    return client.scroll(offset.left, offset.top)
+  }
+}