[WIP] Integrate WDIO

README.md

@@ -29,6 +29,8 @@
 - Plays nice with CI and source control
 - Run globally or locally as a standalone package app or `require('backstopjs')` right into your node app
 - Incredibly easy to use: just 3 commands go a long long way!
+- [BETA] Limited Support for WebDriver Protocol, based on wdio
+   - works as well with any wdio-(cloud)-service (see [wdio configuration]() )
 
 ![BackstopJS cli report](http://garris.github.io/BackstopJS/assets/cli-report.png)
 
@@ -96,14 +98,17 @@ BackstopJS can create a default configuration file and project scaffolding in yo
 ```sh
 $ backstop init
 ```
-
-
 ### Working with your config file
 
 By default, BackstopJS places `backstop.json` in the root of your project. And also by default, BackstopJS looks for this file when invoked.
 
 Pass a `--config=<configFilePathStr>` argument to test using a different config file.
 
+**Propagation of Environment Variables**
+
+To avoid having any hardcoded credentials, you can use "process.env." as prefix for any value in your json config. These values overwritten on runtime.
+Alternativ you can use the `backstop.js` config file.
+
 **JS based config file**
 
 You may use a javascript based config file to allow connents in your config. Be sure to _export your config object as a node module_.
@@ -588,6 +593,30 @@ To use chrome headless you can currently use _puppeteer_ (https://github.com/Goo
 ```json
 "engine": "puppeteer"
 ```
+#### [BETA] WebDriverIO
+
+To use WebDriverIO for Screenshot Comparison Testing you change the engine to
+
+```json
+"engine": "wdio"
+```
+To pass any required additional WDIO Configuration you can configure:
+```json
+ "engineOptions": {
+    "wdio": {
+       [...]
+     }
+  }
+```
+Services can be configured like in wdio. Have a look at their documentation.
+- [FEEDBACK WANTED] Sauce Service - https://webdriver.io/docs/sauce-service
+- [TESTED] Browserstack - https://webdriver.io/docs/browserstack-service
+- [TESTED] Selenium Standalone - https://webdriver.io/docs/selenium-standalone-service
+
+The WDIO Setup is based on [wdio standalone - remote() function](https://webdriver.io/docs/setuptypes/#package-api-1) - it has slightly different configuration.
+#### ⚠️ LIMITATIONS ⚠️
+- Request blocking or interceptions are not possible without additional setup.
+   - you can proxy your whole browser session, configure proxy as capabilities  https://github.com/lightbody/browsermob-proxy
 
 ### Setting Puppeteer option flags
 Backstop sets two defaults for Puppeteer:

backstop.json

@@ -0,0 +1,71 @@
+{
+  "id": "backstop_default",
+  "viewports": [
+    {
+      "label": "phone",
+      "width": 320,
+      "height": 1768
+    }
+  ],
+  "onBeforeScript": "wdio/onBefore.js",
+  "onReadyScript": "wdio/onReady.js",
+  "scenarios": [
+    {
+      "label": "BackstopJS Homepage",
+      "cookiePath": "backstop_data/engine_scripts/cookies.json",
+      "url": "https://garris.github.io/BackstopJS/",
+      "referenceUrl": "",
+      "readyEvent": "",
+      "readySelector": "",
+      "delay": 0,
+      "hideSelectors": [],
+      "removeSelectors": [],
+      "hoverSelector": "",
+      "clickSelector": "",
+      "postInteractionWait": 0,
+      "selectors": [],
+      "selectorExpansion": true,
+      "expect": 0,
+      "misMatchThreshold": 0.1,
+      "requireSameDimensions": true
+    }
+  ],
+  "paths": {
+    "bitmaps_reference": "backstop_data/bitmaps_reference",
+    "bitmaps_test": "backstop_data/bitmaps_test",
+    "engine_scripts": "backstop_data/engine_scripts",
+    "html_report": "backstop_data/html_report",
+    "ci_report": "backstop_data/ci_report"
+  },
+  "report": [
+    "browser"
+  ],
+  "engine": "wdio",
+  "engineOptions": {
+    "wdio": {
+      "logLevel": "trace",
+      "protocol": "http",
+      "hostname": "hub.browserstack.com",
+      "capabilities": {
+        "browserName": "chrome"
+      },
+      "user": "process.env.BROWSERSTACK_ACCESS_USER",
+      "key": "process.env.BROWSERSTACK_ACCESS_KEY",
+      "services": [
+        [
+          "browserstack", {
+          "browserstackLocal": true
+        }]
+      ]
+    },
+    "puppeteer": {
+      "args": [
+        "--no-sandbox"
+      ]
+    }
+  },
+  "asyncCaptureLimit": 5,
+  "asyncCompareLimit": 50,
+  "debug": false,
+  "debugWindow": false
+}

backstop_data/engine_scripts/cookies.json

@@ -0,0 +1,14 @@
+[
+  {
+    "domain": ".www.yourdomain.com",
+    "path": "/",
+    "name": "yourCookieName",
+    "value": "yourCookieValue",
+    "expirationDate": 1798790400,
+    "hostOnly": false,
+    "httpOnly": false,
+    "secure": false,
+    "session": false,
+    "sameSite": "no_restriction"
+  }
+]

backstop_data/engine_scripts/puppet/clickAndHoverHelper.js

@@ -0,0 +1,39 @@
+module.exports = async (page, scenario) => {
+  const hoverSelector = scenario.hoverSelectors || scenario.hoverSelector;
+  const clickSelector = scenario.clickSelectors || scenario.clickSelector;
+  const keyPressSelector = scenario.keyPressSelectors || scenario.keyPressSelector;
+  const scrollToSelector = scenario.scrollToSelector;
+  const postInteractionWait = scenario.postInteractionWait; // selector [str] | ms [int]
+
+  if (keyPressSelector) {
+    for (const keyPressSelectorItem of [].concat(keyPressSelector)) {
+      await page.waitFor(keyPressSelectorItem.selector);
+      await page.type(keyPressSelectorItem.selector, keyPressSelectorItem.keyPress);
+    }
+  }
+
+  if (hoverSelector) {
+    for (const hoverSelectorIndex of [].concat(hoverSelector)) {
+      await page.waitFor(hoverSelectorIndex);
+      await page.hover(hoverSelectorIndex);
+    }
+  }
+
+  if (clickSelector) {
+    for (const clickSelectorIndex of [].concat(clickSelector)) {
+      await page.waitFor(clickSelectorIndex);
+      await page.click(clickSelectorIndex);
+    }
+  }
+
+  if (postInteractionWait) {
+    await page.waitFor(postInteractionWait);
+  }
+
+  if (scrollToSelector) {
+    await page.waitFor(scrollToSelector);
+    await page.evaluate(scrollToSelector => {
+      document.querySelector(scrollToSelector).scrollIntoView();
+    }, scrollToSelector);
+  }
+};

backstop_data/engine_scripts/puppet/ignoreCSP.js

@@ -0,0 +1,65 @@
+/**
+ * IGNORE CSP HEADERS
+ * Listen to all requests. If a request matches scenario.url
+ * then fetch the request again manually, strip out CSP headers
+ * and respond to the original request without CSP headers.
+ * Allows `ignoreHTTPSErrors: true` BUT... requires `debugWindow: true`
+ *
+ * see https://github.com/GoogleChrome/puppeteer/issues/1229#issuecomment-380133332
+ * this is the workaround until Page.setBypassCSP lands... https://github.com/GoogleChrome/puppeteer/pull/2324
+ *
+ * @param      {REQUEST}  request
+ * @return     {VOID}
+ *
+ * Use this in an onBefore script E.G.
+  ```
+  module.exports = async function(page, scenario) {
+    require('./removeCSP')(page, scenario);
+  }
+  ```
+ *
+ */
+
+const fetch = require('node-fetch');
+const https = require('https');
+const agent = new https.Agent({
+  rejectUnauthorized: false
+});
+
+module.exports = async function (page, scenario) {
+  const intercept = async (request, targetUrl) => {
+    const requestUrl = request.url();
+
+    // FIND TARGET URL REQUEST
+    if (requestUrl === targetUrl) {
+      const cookiesList = await page.cookies(requestUrl);
+      const cookies = cookiesList.map(cookie => `${cookie.name}=${cookie.value}`).join('; ');
+      const headers = Object.assign(request.headers(), { cookie: cookies });
+      const options = {
+        headers: headers,
+        body: request.postData(),
+        method: request.method(),
+        follow: 20,
+        agent
+      };
+
+      const result = await fetch(requestUrl, options);
+
+      const buffer = await result.buffer();
+      let cleanedHeaders = result.headers._headers || {};
+      cleanedHeaders['content-security-policy'] = '';
+      await request.respond({
+        body: buffer,
+        headers: cleanedHeaders,
+        status: result.status
+      });
+    } else {
+      request.continue();
+    }
+  };
+
+  await page.setRequestInterception(true);
+  page.on('request', req => {
+    intercept(req, scenario.url);
+  });
+};

backstop_data/engine_scripts/puppet/interceptImages.js

@@ -0,0 +1,37 @@
+/**
+ * INTERCEPT IMAGES
+ * Listen to all requests. If a request matches IMAGE_URL_RE
+ * then stub the image with data from IMAGE_STUB_URL
+ *
+ * Use this in an onBefore script E.G.
+  ```
+  module.exports = async function(page, scenario) {
+    require('./interceptImages')(page, scenario);
+  }
+  ```
+ *
+ */
+
+const fs = require('fs');
+const path = require('path');
+
+const IMAGE_URL_RE = /\.gif|\.jpg|\.png/i;
+const IMAGE_STUB_URL = path.resolve(__dirname, '../../imageStub.jpg');
+const IMAGE_DATA_BUFFER = fs.readFileSync(IMAGE_STUB_URL);
+const HEADERS_STUB = {};
+
+module.exports = async function (page, scenario) {
+  const intercept = async (request, targetUrl) => {
+    if (IMAGE_URL_RE.test(request.url())) {
+      await request.respond({
+        body: IMAGE_DATA_BUFFER,
+        headers: HEADERS_STUB,
+        status: 200
+      });
+    } else {
+      request.continue();
+    }
+  };
+  await page.setRequestInterception(true);
+  page.on('request', intercept);
+};

backstop_data/engine_scripts/puppet/loadCookies.js

@@ -0,0 +1,33 @@
+const fs = require('fs');
+
+module.exports = async (page, scenario) => {
+  let cookies = [];
+  const cookiePath = scenario.cookiePath;
+
+  // READ COOKIES FROM FILE IF EXISTS
+  if (fs.existsSync(cookiePath)) {
+    cookies = JSON.parse(fs.readFileSync(cookiePath));
+  }
+
+  // MUNGE COOKIE DOMAIN
+  cookies = cookies.map(cookie => {
+    if (cookie.domain.startsWith('http://') || cookie.domain.startsWith('https://')) {
+      cookie.url = cookie.domain;
+    } else {
+      cookie.url = 'https://' + cookie.domain;
+    }
+    delete cookie.domain;
+    return cookie;
+  });
+
+  // SET COOKIES
+  const setCookies = async () => {
+    return Promise.all(
+      cookies.map(async (cookie) => {
+        await page.setCookie(cookie);
+      })
+    );
+  };
+  await setCookies();
+  console.log('Cookie state restored with:', JSON.stringify(cookies, null, 2));
+};

backstop_data/engine_scripts/puppet/onBefore.js

@@ -0,0 +1,3 @@
+module.exports = async (page, scenario, vp) => {
+  await require('./loadCookies')(page, scenario);
+};

backstop_data/engine_scripts/puppet/onReady.js

@@ -0,0 +1,6 @@
+module.exports = async (page, scenario, vp) => {
+  console.log('SCENARIO > ' + scenario.label);
+  await require('./clickAndHoverHelper')(page, scenario);
+
+  // add more ready handlers here...
+};

backstop_data/engine_scripts/puppet/overrideCSS.js

@@ -0,0 +1,15 @@
+const BACKSTOP_TEST_CSS_OVERRIDE = `html {background-image: none;}`;
+
+module.exports = async (page, scenario) => {
+  // inject arbitrary css to override styles
+  await page.evaluate(`window._styleData = '${BACKSTOP_TEST_CSS_OVERRIDE}'`);
+  await page.evaluate(() => {
+    const style = document.createElement('style');
+    style.type = 'text/css';
+    const styleNode = document.createTextNode(window._styleData);
+    style.appendChild(styleNode);
+    document.head.appendChild(style);
+  });
+
+  console.log('BACKSTOP_TEST_CSS_OVERRIDE injected for: ' + scenario.label);
+};

backstop_data/engine_scripts/wdio/clickAndHoverHelper.js

@@ -0,0 +1,42 @@
+module.exports = async (browser, scenario) => {
+  const hoverSelector = scenario.hoverSelectors || scenario.hoverSelector;
+  const clickSelector = scenario.clickSelectors || scenario.clickSelector;
+  const keyPressSelector = scenario.keyPressSelectors || scenario.keyPressSelector;
+  const scrollToSelector = scenario.scrollToSelector;
+  const postInteractionWait = scenario.postInteractionWait; // selector [str] | ms [int]
+
+  if (keyPressSelector) {
+    for (const keyPressSelectorItem of [].concat(keyPressSelector)) {
+      await browser.$(keyPressSelectorItem.selector).waitForDisplayed();
+      const input = browser.$(keyPressSelectorItem.selector);
+      input.setValue(keyPressSelectorItem.keyPress);
+    }
+  }
+
+  if (hoverSelector) {
+    for (const hoverSelectorIndex of [].concat(hoverSelector)) {
+      await browser.$(hoverSelectorIndex).waitForDisplayed();
+      browser.$(hoverSelectorIndex).moveTo();
+    }
+  }
+
+  if (clickSelector) {
+    for (const clickSelectorIndex of [].concat(clickSelector)) {
+      await browser.$(clickSelectorIndex).waitForDisplayed();
+      const clickElement = browser.$(clickSelectorIndex);
+      clickElement.click();
+    }
+  }
+
+  if (postInteractionWait) {
+    await browser.$(postInteractionWait).waitForDisplayed();
+  }
+
+  if (scrollToSelector) {
+    await browser.$(scrollToSelector).waitForDisplayed();
+
+    await browser.execute(scrollToSelector => {
+      document.querySelector(scrollToSelector).scrollIntoView();
+    }, scrollToSelector);
+  }
+};