One mistake many people make is running their selenium test suites with every browser combination... you don't need to! Rendering problems are probably the biggest cross browser compatibility issue, and you can't actually test for these with Functional Tests. So by running Selenium tests across many browsers you are really testing JavaScript and DOM compatibility. Running our Selenium tests across many browsers was our JavaScript compatibility strategy, but it proved inefficient as we ended up with bugs in Internet Explorer; how embarrassing!

1. Cross Browser testing JavaScript
Alan Parkinson
CEO, Hindsight Software Ltd
@alan_parkinson

3. You don’t need to run your Selenium Test
suite with every browser*
The Truth

4. • No visual testing
• Low JavaScript code coverage
• Costly to improve coverage
Rendering Compatibility
JavaScript/DOM Compatibility
What do we achieve?

5. • JavaScript and DOM compatibility
• Good code coverage
• Reusing a development artifact
Run all JavaScript unit tests cross browser
Simple Answer

6. • Average Test: 8 Seconds
• Test Suite: 5 minutes
• Average Test: 0.1 seconds
• Test suite: 11 seconds
Functional Tests
JavaScript Unit Tests
Looking at the numbers

7. Do we meet our compatibility objective?
Code Coverage has a use

8. • Too many JavaScript files
• Order of loading files
Not everything will be picked up by Unit
Tests
*The qualifier
Only run critical functional tests cross-
browser

9. JAVASCRIPT TEST RUNNERS
Reusing your Selenium infrastructure

10. • Testing Framework Agnostic
• Continuous Integration
• Code coverage with Instanbul
• Launch Browsers
• Manually connect browsers
Spectacular Test Runner for JavaScript
Real Browsers
Karma

11. • Connects Remote WebDriver Instances
• Selenium Grid 2
• Supports Desired Capabilities
Reusing your Selenium Infrastructure
Karma WebDriver Launcher

12. Karma in action
$ npm install -g karma
$ npm install -g karma-webdriver-launcher

13. Continuous Integration
Override karma.conf.js from the command line
singleRun: true
reporters: [‘junit’]

14. • Code Coverage
• Feedback time
• Meeting our objective - Compatibility
• Karma Runner
• Use your existing WebDriver infrastructure
• Use code coverage to validate the majority of your code
is compatibility tested.
Functional tests have poor performance:
Cross-browser unit test JavaScript
Summary

15. http://karma-runner.github.io/
https://github.com/hindsightsoftware/karma-
webdriver-example
Thank you
Alan Parkinson
@alan_parkinson