Speed Up Your Selenium Tests with PhantomJS
Ivan De Marino - Senior Software Engineer / Neustar, Inc.
Selenium Conference - April 2012

Who is Ivan De Marino?

Senior Engineer at Neustar

Contributor to PhantomJS

Spend lots of my time

• github.detro = ivan.convert(italian_espresso || starbucks_espresso);
• twitter.detronizator = ivan.rant(news || humor || software || {});
• food = ivan.italian.cook(recipe || random_ingredients);
• ivan.cycle(good_bike).performance < semi_pro_cyclist.performance;

Only used Selenium for a few months

Neustar WPM Agent

My team is responsible for the "Super" Agent:

• Service that executes Customer Tests, leveraging Selenium and other projects
• Back-end component running on EC2, Rackspace, Voxel, ...
• Tests written in Javascript
• Custom API mixed with Javascript-to-Selenium bridge
• Test Execution Speed is key measurment: some customer scripts require minutes to run!

We are Hiring!!!

via Wordle

PhantomJS: What's all the fuss about?

• Headless (Qt)WebKit
• JavaScript-driven: high hackability
• Ideal for Testing
  • pre-commit hook
  • headless is cloud-friendly
• Momentum
  • Many users and lots of feedback
  • Regular releases
  • Thanks to Ariya Hidayat (Project Leader)
• Integration: Poltergeist, CasperJS and many more

fLeXibLe

PhantomJS is flexible

Every thing you need in 20 lines!

Prototype Boeing Phantom Ray [via Wikipedia]

PhantomJS aims at being fast

• Written in (good) Qt C++
• no_UI === no_Drawing === low_memory_and_CPU_footprint
• Very easy to get started (that counts as speed too!!!)
• Whole test suite in ~2s on my 4yo iMac
• Maybe V8 in the future (depends on QtWebKit)

PhantomJS does have (some) drawbacks

• Only WebKit engine (for now...)
• QtWebKit != Safari != Chrome != MOBILE_OS_HERE
• Asynchronous API: not everyone's cup of tea
• Limited/No plugin support (working on a solution)

How much do you value your time?
Busy Life, Bloor Street [via]

Time is usually interpreted as:

$\mathrm{Time}=\frac{\mathrm{Distance}}{\mathrm{Speed}}$

So what we need is
SPEED!
"... or less Distance!"
John Bower

How long does it take do a test?

$\mathrm{test.coding.time}=\mathrm{test.coding.write(platform.ease)}\mathrm{test.result.time}=\mathrm{test.exec(platform.speed,\; project.size)}\mathrm{test.time}\approx 0^{\mathrm{i}}\mathrm{test.coding.time}+n\mathrm{test.result.time}$

Classic example: "Google Cheese!" Test

We need to
reduce( test.result.time )

3~5s
is good for overnight tests,
but not so good for coding turnaround

GhostDriver
github/ghostdriver

What's GhostDriver?

• Implementation of WireProtocol on PhantomJS
• 100% Javascript
• Stress test for PhantomJS require("webserver") module
• Most starred issue (#49) on the official PhantomJS tracker
• RemoteWebDriver Server

GhostDriver vs. "Google Cheese!" Test?

Demo
mvnexec.sh & mvnexec-server.sh

Timing when starting/stopping the Driver: 5 iterations / 100 iterations

Timing when in server mode: 5 iterations / 100 iterations

PhantomJS + GhostDriver: Pros & Cons

Pros

• Fast test results => faster coding turnaround
• Enhanced dev environment
  • store it in your repo for easy setup (max ~15MB of binary)
  • launch Selenium tests in your pre-commit hook
  • headless is cloud-friendly
• Hackable and tunable (JavaScript / C++)
• VERY FAST in server configuration

Cons

• PhantomJS ≈ real browser
• Only 13 of of 95 Wire Protocol commands implemented (13.68%)

GhostDriver: Project Status

• Not ready for production
• Project just started (only 1 week of real, solid coding)
• Help! FORK and HACK with me
• Future Neustar WPM offering
• Important items in the TODO list:
  • Multiple Frames per Window
  • Proxy
  • Screenshot
  • Capabilities negotiation
  • Tailored (Java) Bindings
  • 100% Wire Protocol Commands
  • Merge into Selenium, IFF Git ;-)

Thanks!
Questions?
github/detro/ghostdriver - github/ariya/phantomjs

Appendix: A bit of Architecture