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• Install
• Taking screenshots
  • screenshot CLI Options
  • Config the setup.json
    • Parameters
      • Sample file:
  • Config the pages.json
    • Parameters
      • Sample file:
• Comparing screenshots
  • compare CLI Options

Install

Clone this repository and run:

$ npm install

Taking screenshots

$ node screenshot.js

screenshot CLI Options

  -h, --help                 Print out helpful information.
  -l, --loglevel Number      Log level. Default 0
                             0=Silent, 1=Important only, 2=All.
  -d, --domain String        Main domain to be tested. When set, it OVERRIDES the "domain" parameter from
                             the pages.json file.
  -a, --auth String:String   username:password for the http authentication. When set, it OVERRIDES the
                             "authenticate" parameter from the pages.json file.
  -e, --headless Boolean     Set Puppeteer to run in the headless mode. When set, it OVERRIDES the
                             "headless" parameter from the setup.json file.
  -p, --pages String         The path to the pages.json file. Default option uses pages.json from the root
                             of the project.

Config the setup.json

Parameters

• screenshotsFolder <string> Destination folder for the image files. Default screenshots
• autoScroll <Boolean> Option for Puppeteer to scroll automatically to the bottom of the page before screenshot. Useful for scroll incrementally through a page in order to deal with lazy loaded elements. It scrolls in 100px every 100ms until the bottom of the page. Default true
• pages <string> Path and file name of pages list. Default pages.json
• puppeteer <Object> <Puppeteer> config object. Default:
  • launch <boolean> Whether to use or not the headless mode. Default true
  • emulate <Array> Array of objects following the Puppeteer DeviceDescriptors.ts standards. In order to test different resolutions emulating the same browser, just add the width in the name parameter. E.g.: "name": "Chrome 1024".
• diffFolder <string> Destination folder for the comparison image files. Default screenshots/_diff
• resembleOptions <Object> Resemblejs configuration options.

Sample file:

{
	"screenshotsFolder": "screenshots",
	"pages": "pages.json",
	"puppeteer": {
		"launch": {
			"headless": true
		},
		"emulate": [
			{
				"name": "Chrome 1280",
				"userAgent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.181 Safari/537.36",
				"viewport": {
					"width": 1280,
					"height": 780
				}
			},
			{
				"name": "iPhone 6",
				"userAgent": "Mozilla/5.0 (iPhone; CPU iPhone OS 11_0 like Mac OS X) AppleWebKit/604.1.38 (KHTML, like Gecko) Version/11.0 Mobile/15A372 Safari/604.1",
				"viewport": {
					"width": 375,
					"height": 667,
					"deviceScaleFactor": 2,
					"isMobile": true,
					"hasTouch": true,
					"isLandscape": false
				}
			}
		]
	},

	"diffFolder": "diff",
	"resembleOptions": {
		"output": {
			"errorColor": {
				"red": 255,
				"green": 0,
				"blue": 255
			},
			"errorType": "movement",
			"transparency": 1,
			"largeImageThreshold": 5000,
			"useCrossOrigin": false,
			"outputDiff": true
		},
		"scaleToSameSize": false,
		"ignore": "colors"
}

Config the pages.json

Parameters

• domain <string> Main domain to be tested. It is concatenated with the pages.url.
• authenticate <Object> Object credentials for http authentication. See more at Puppeteer page.authenticate documentation. If username or password equal to null, will not run the page.authenticate method.
  • username <string> Default null
  • password <string> Default null
• pages <Array> Array of objects containing information about the pages to be tested.
  • url <string> URL path. It is also used to create a unique filename for each image so, it is important to have a unique url name. If you want to test mutiple scenarios from the same page, use some querystring to identify it otherwise the last file will override the previous one.
  • click <array> Array of elements to be clicked. Each element is a selector to search for element to click. If there are multiple elements satisfying the selector, the first will be clicked. It follows the same behavior of the document.querySelectorAll of javascript.
  • waitFor If follows the Puppeteer page.waitFor documentation.

Actions will follow the order:

 Page load event → autoScroll → click → waitFor → screenshot

Sample file:

{
	"domain": "http://www.yoursupercoolsite.com",
	"authenticate": {
		"username": null,
		"password": null
	},
	"pages": [
		{ "url": "/", "click": ["#mainbutton"]},
		{ "url": "/?complex-selector", "click": [".menu-secondary > ul > li:nth-child(2) > .link"]},
		{ "url": "/?3-buttons", "click": ["#firstbutton", ".secondbutton", "#send-form a"]},
		{ "url": "/?click-and-wait", "click": ["#mainbutton"], "waitFor": 5000},
		{ "url": "/contact"},
		{ "url": "/products"},
		{ "url": "/products/product-1"},
		{ "url": "/products/product-2"},
		{ "url": "/products/product-3"}
	]
}

Comparing screenshots

The compare.js script compares two image folders, generates the diff images inside a folder. The diff destination folder can be set inside the setup.json file by the diffFolder parameter.

When screenshot.js runs, it creates a folder inside screenshots using a timestamp format (YYYY.MM.DD-HH.MM.SSSS) to avoid folder naming conflic and overriding. E.g.: 2018.07.05-16.34.929.

Inside the "timestamp" folder, it creates a folder structure for each "device" name. E.g.:

./screenshots/2018.07.05-16.34.929/
              ├── chrome-1280/
              ├── chrome-1024/
              ├── iphone-6/
              ...

It is mandatory to set a --base and --compare folder and they must be the "timestamp" folder so, the script will search for the images in the "device" child folders.

In order to make easier to use the compare CLI, you can rename your "timestamp" folder to a easier name do recall such as "production" and "staging". E.g.:

./screenshots/production/
              ├── chrome-1280/
              ├── chrome-1024/
              └── iphone-6/
./screenshots/staging/
              ├── chrome-1280/
              ├── chrome-1024/
              └── iphone-6/

compare CLI Options

$ node compare.js

Options List

  -h, --help              Print out helpful information.
  -l, --loglevel Number   Log level. Defalut 0
                          0=Silent, 1=Important only, 2=All.
  -b, --base String       Path to the folder used as the base for comparison.
  -c, --compare String    Path to the folder used for comparison against the base folder.
  -d, --dry-run           Compares the images without saving the diff files.