Selenium in real world
projects
Automated testing of web applications
Martin Kleppmann
Ept Computing | www.eptcomputing.com

Deploying a
new release
http://flickr.com/photos/josa/124264708/ (creative commons)

http://flickr.com/photos/dennissylvesterhurd/200001422/ (creative commons)

Selenium

Model-View-Controller
Controller
Unit testing
Request
Client
Model DB
Response
View

Build cycle
Checkout latest version
Run unit/model tests
Migrate staging database
10 mins
Deploy to staging server
Fill database with example data
Render lots of views: wget -r
Run Selenium scripts
Notify us of outcome

Model-View-Controller
Selenium
testing
Controller
Unit testing
Request
Client
Model DB
Response
View
wget -r

Functional stack
Rendering on screen
DOM (Document tree) Selenium
HTML
wget -r
HTTP
Web framework Model test
Database

Sample script
# User is not logged in. Searches for auction and chooses it in the listing
selenium.type \"search_query\", \"selenium\"
selenium.click \"commit\"
selenium.wait_for_page_to_load \"30000\"
selenium.click \"link=Selenium test auction, single lot, normal+buy now\"
selenium.wait_for_page_to_load \"30000\"
# User places a bid of 12 pounds (below the reserve price)
selenium.type \"bid_max_price_vatted\", \"12\"
selenium.click \"bid_submit\"
selenium.wait_for_page_to_load \"30000\"
# User logs in as Adalbert
selenium.type \"login\", \"adalbert\"
selenium.type \"password\", \"asdf\"
selenium.click \"commit\"
selenium.wait_for_page_to_load \"30000\"
# Bid confirmation page
selenium.click \"bid_submit\"
selenium.wait_for_page_to_load \"30000\"
# Redirected to auction page - check Adalbert is losing
assert selenium.is_text_present(\"You are losing your bid on this auction\")
assert selenium.is_text_present(\"below the seller's reserve price\")

Demo

Selenium strong points
• Simple and powerful DOM-level testing
• Fairly stable – ok for continuous integration
• Ajax-heavy apps (cross-browser issues)
• Testing typical user flows
• Good fit with Agile et al.
• Open Source

Selenium weak points
• Fiddly setup, platform maintenance
• Tedious error diagnosis
• Valid UI changes may break test
• Rendering tests limited
• Interaction with Flash
• Slow; concurrency problematic
• Heavily dependent on state – generate data

The future
• “Selenium on demand” service – “rent a
web browser”, large choice of platforms
• Acceptance testing; testing impact of ads
• Memory leak detection
• Access to email in tests
• etc...