Bartender

Browser Automated Render Testing Driver: Automated testing of browser rendering engines using Clojure, generative (property-based) testing, formal grammars (EBNF), and a consensus test oracle.

Also refer to Instacheck which is leveraged for the core weighted grammar and property-based testing engine.

Prerequisites

• Install libopencv-dev:

sudo apt-get install libopencv-dev

• Generate the opencv maven artifactrs:

make deps

• Compile ClojureScript Report page application:

lein cljsbuild once send

• Download/build the drivers/browsers that you want to test:
  • Firefox (https://developer.mozilla.org/en-US/Firefox/Headless_mode):

  curl -L https://github.com/mozilla/geckodriver/releases/download/v0.22.0/geckodriver-v0.22.0-linux64.tar.gz | tar xvzf -
  

  • Chrome (https://sites.google.com/a/chromium.org/chromedriver/getting-started):

  curl -LO https://chromedriver.storage.googleapis.com/2.35/chromedriver_linux64.zip
  unzip chromedriver_linux64.zip; rm chromedriver_linux64.zip
  

  • Brave (https://github.com/brave/brave-browser/releases/):

  wget https://github.com/brave/brave-browser/releases/download/v0.56.15/chromedriver-v2.33-linux-x64.zip
  

  • Servo (https://github.com/mozilla/servo):

  git clone https://github.com/servo/servo
  cd servo
  #./mach build --release
  time RUSTFLAGS='-L ./support/linux/gstreamer/gst/lib' ./mach build --release
  

  • If using BrowserStack you will need to download the local testing proxy that allows BrowserStack to load test pages from the local system:

  wget https://www.browserstack.com/browserstaclocal/BrowserStackLocal-linux-x64.zip
  unzip BrowserStackLocal-linux-x64.zip
  

Running Tests (rend)

• Start the drivers/browsers/servers:

  • Firefox:

  ./geckodriver --port 7000
  

  • Chrome:

  ./chromedriver --port=7001
  

  • Servo (https://github.com/mozilla/servo):

  ./mach run --release -z --webdriver=7002 --resolution=400x300
  

  • Brave:

  ./brave/chromedriver --port=7003
  

  • If using BrowserStack, start the BrowserStack local server:

  ./BrowserStackLocal --key KEY
  

• Update config.yaml with browser webdriver connection information

• Start a test run:

lein run tests config.yaml

Monitor results at http://localhost:3000 (3000 is the :web :port specified in config.yaml).

Extract/parse weights from an existing web page (wend)

time lein run parse --weights-output data/my-page.edn my-page.html

This can then be used to generate and test with similarly weighted pages by updating the config yaml:

...
weights:
    start: data/my-pages.edn
...

lein run tests config.yaml

You can then connect to http://localhost:3000 (config file default) to view a report/log of the tests as they run.

How it works

This needs to be greatly expand but here is a very rough outline:

• mend: The mend module (described below) only needs to be executed directly when the HTML5 or CSS3 grammars are updated. It performs the following:
  • The HTML5 and CSS3 EBNF grammars from kanaka/html5-css3-ebnf are translated to Clojure test.check generator code using Instacheck.
  • instaparse grammars for parsing are also cached to resources/html5.grammar and resources/css3.grammar.
• rend: The rend module does the following:
  • Load yaml config file specified on the command line
  • Start a web server (for page loading and report UI)
  • Connect to each configured browser (via webdriver)
  • Run 1 or more test runs. Each run uses quick-check (via Instacheck) to do the following:
    • Generate random test cases (HTML5 and CSS3 web pages) of increasing size.
    • Load each test case on all browsers, screenshot the results and compare.
    • If a difference above the configured threshold is detected then the shrinking process begins.
    • New test cases are generated and loaded/compared to try and find progressively smaller test cases that still cause a rendering difference.
    • If a reduction mode is specified, then after the shrinking process is complete, the shrunk test case is parsed to extract weights for the case and these weights are used to run a reduction algorithm on the weights in preparation for the next test run. This reduction step is to try and reduce the likelihood of finding the same test again in the next run.
• send: The send module is a reagent/React web application that dynamically reports on the state of server testing. The app keeps its state in sync with the server by connecting with WebSockets and receiving state delta messages.
• wend: The wend module (described above) allows existing test cases to be parsed to extract their grammar weight values. The extract weights can then be used to try and produce test cases that have similar characteristics to the existing test case. Specifically this is designed to enable shrinking of existing test cases.

Browser Configuration

Here is example yaml configuration file that connects to Firefox (geckodriver) and Chrome (chromedriver) running locally:

test:
    runs: 5
start-seed: 2
quick-check:
    iterations: 20
    max-size: 100
weights:
    base: ["resources/html5-weights.edn", "resources/css3-weights.edn"]
    fixed: "resources/fixed-weights.edn"
compare:
    method: SQDIFF_NORMED
    threshold: 0.00003
web:
    host: 127.0.0.1
    port: 3000
    dir: "gen"
browsers:
    firefox:
      url: "http://localhost:7000"
      capabilities: {"moz:firefoxOptions":
                     {"args": ["--headless"]}}
    chrome:
      url: "http://localhost:7001"
      capabilities: {"chromeOptions":
                     {"args": ["--headless"]}}

Here is the browser section of a yaml configuration file that connects to three browsers running in BrowserStack:

...
browsers:
    bs-chrome-win-62:
      url: "https://USER:KEY@hub-cloud.browserstack.com/wd/hub"
      capabilities: {"browserstack.local": true,
                     "browser": "Chrome",
                     "browser_version": "69.0",
                     "os": "Windows",
                     "os_version": "10",
                     "resolution": "1024x768"}
    bs-firefox-win-62:
      url: "https://USER:KEY@hub-cloud.browserstack.com/wd/hub"
      capabilities: {"browserstack.local": true,
                     "browser": "Firefox",
                     "browser_version": "62.0",
                     "os": "Windows",
                     "os_version": "10",
                     "resolution": "1024x768"}
    bs-edge-win-17:
      url: "https://USER:KEY@hub-cloud.browserstack.com/wd/hub"
      capabilities: {"browserstack.local": true,
                     "browser": "Edge",
                     "browser_version": "17.0",
                     "os": "Windows",
                     "os_version": "10",
                     "resolution": "1024x768"}

Update HTML5 and CSS3 Generators (mend)

Generate Clojure generator source based on the HTML5 and CSS3 EBNF grammars from kanaka/html5-css3-ebnf. You should only need to do the following if manual changes have been made to the EBNF grammars or the grammar fixups/mangles in src/mend/grammar.clj.

time lein run translate --mode html --namespace rend.html5-generators --function html5-generators --weights-output resources/html5-weights.edn --clj-output resources/rend/html5_generators.clj

Generate Clojure generator source based on the CSS3 EBNF grammar (warning this requires about 2GB of free memory):

time lein run translate --mode css --namespace rend.css3-generators --function css3-generators --weights-output resources/css3-weights.edn --clj-output resources/rend/css3_generators.clj

Use the generators from a Clojure REPL:

lein repl
(require '[rend.generator])
(in-ns 'rend.generator)
(clojure.pprint/pprint (gen/sample (get-html-generator) 5))

Images

The following images are included in static/:

• File:Books-aj.svg_aj_ashton_01g*.png (Public Domain)
• B_stop.svg (CC0)
• Eilat_-_Dolphin_reef*.jpg (CC BY-SA 3.0)
• SpaceX_Kestrel_engine2*.gif (CC BY-SA-3.0)

License

Copyright © Joel Martin

Distributed under the Mozilla Public License either version 2.0 or (at your option) any later version.