Selenium at Salesforce Scale

Learn about Salesforce's inventory of 100,000 Selenium tests, how we run them at scale, and how to architect your test harness for success.

Transcript

1. Selenium at Salesforce Scale Greg Wester Principal Engineer @gwestr in/gwester
2. • About Salesforce engineering • Operating a selenium farm • Selenium design patterns • Overcoming test failures • Q&A Agenda
3. Salesforce Scale • 3:2 ratio for developers : quality engineers • everyone is a software engineer; role varies • 2 selenium committers on staff (Jim Evans, Luke Inman) • 50,000 VM data center for automated tests • multimillion dollar investment • 500 commits per day • ~120 software engineering teams
4. Why Salesforce loves WebDriver WebDriver is the only test framework in our current arsenal that truly mimics an end-user’s experience • We don’t mock anything • We test against a live app • We suffer the pain of latency • We test end to end on almost every action WebDriver tests can catch things other levels of tests can’t • Multi-platform consistency • DOM consistency • Rendering issues • Piping between app layers source: watirmelon.com © Alister Scott
5. UI Testing Portfolio • 50,000 unique Selenium tests • 7,500 unique WebDriver tests • full “browser compatibility”: IE6-IE11, Firefox, Chrome, Safari • some can run in headless browser like Phantom JS • 2,000 javascript unit tests • no DOM required • 10ms average execution time source: watirmelon.com © Alister Scott
6. 1,000,000 browser tests per day • Click here to add bullets
7. Issues of scale • Assigning test failures to the responsible engineer • Non deterministic tests (flappers) and re-runs • Selenium jar upgrades are challenging • Browser upgrades are challenging • IT and automation ops provide different versions • Large suites: adjust run frequency, deprecate old tests
8. Salesforce UI Testing Pattern • Click here to add bullets
9. Proper Page Objects Encapsulate Selenium • Make an API of your page for your test • No imports for “openqa” or “selenium.org” in your test • All references to driver & selenium in the page object • Fail fast - call the page object factory in test setup • No assertions in page objects (or any test utility) • Share page objects across engineering teams • developer complete UI should have a page object • if you can’t make one it’s not a testable page • dependency challenges at scale
10. Challenges for Mobile Platforms • Adapting page objects to platform specific UI elements • Screen sizes and adaptive layouts • cards • “stage left” • lightweight page objects = widgets • Avoid browser or platform specific code in actual tests • establish context elsewhere in utils or page objects • Automated tests in emulators (99%+) • manual tests on devices before release • exception: testing video
11. Sagar Wanaselja Lead Engineer swanaselja@salesforce.com
12. Problematic WebDriver Test
13. Better WebDriver Test
14. PageObject WebDriver Test
15. Diagnosing Test Failures • Screenshot and HTML capture at failure point • AssertionError or RuntimeException • Differences between localhost and automation VM • Optimistic timing assumptions • javascript, rendering, server response, etc. • Defensive “negative” testing • Getting to 100% tests passing
16. Pro Tips • Version tests and app code (and configuration) together • Use the Page Object model • Use the API to set up the test, not the UI • Anticipate Selenium and Browser releases • Allocate capacity to browsers most used by customers • log the user agent on every page view
17. More Pro Tips • Avoid using xpath selectors • Complex DOM makes xpath evaluation much slower • Some xpaths are not properly evaluated in WebDriver • When working with pop ups make sure you return focus to the main window • For static HTML pages consider HTML Unit
18. Mature Quality Strategies • Selenium for dynamic security vulnerability analysis • Pixel perfect image diffs • Accessibility testing (tab completion) • Testing javascript with unit tests • Selenium is for testing browser compatibility and DOM