Using The Page Object Pattern
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The document discusses the Page Object Pattern, a technique for improving the maintainability of functional test code by promoting reuse and reducing duplication. It highlights how this approach enhances test readability and robustness, particularly beneficial for rapidly evolving applications, and introduces method chaining to further streamline test creation. The presentation also critiques Selenium IDE's limitations and emphasizes the need for coding tests in a programming language to achieve better maintainability.
Using The Page Object Pattern
- 1. Using the Page Object Pattern to Improve Functional Test Maintainability Dante Briones Principal Consultant Electronic Ingenuity LLC http://electronicingenuity.com Friday, 07 August, 2009
- 2. The Page Object Pattern • Technique for structuring test code that: • Promotes reuse and reduces duplication • Makes tests readable • Makes tests more robust (less brittle) • Improves maintainability, particularly if the application is rapidly evolving Friday, 07 August, 2009
- 3. The Page Object Pattern • Demos will be coded in Java • Everything we discuss is applicable to other strongly-typed languages (e.g. C#) • Most things are applicable to dynamically- typed languages (e.g. Ruby, Python, Perl) Friday, 07 August, 2009
- 4. Selenium IDE Quick Poll • How many using Se IDE? • How many create tests primarily through record & playback? Friday, 07 August, 2009
- 5. Selenium IDE It’s Great Because: • It’s Free • It’s Free • Requires little or no programming experience Friday, 07 August, 2009
- 6. Selenium IDE It falls short because: • Selenese is not a programming language • No support for loops/iteration • No support for conditionals (if...else) • No way to eliminate duplicated code! Friday, 07 August, 2009
- 7. Selenium IDE Why is duplication bad? • Has this ever happened to you? • A tiny change to the app causes several test failures? • Let’s see an example Friday, 07 August, 2009
- 8. Demo Friday, 07 August, 2009
- 9. Selenium IDE Why is duplication bad? • Fixing the tests will require more work than the change that caused the failure • Duplication makes code less maintainable Friday, 07 August, 2009
- 10. Selenium IDE Summary • Great productivity for the first few tests • Maintainability decreases as the test suite grows • How can we do better? Friday, 07 August, 2009
- 11. Start Coding Your Tests a.k.a. “Write tests in a programming language” Friday, 07 August, 2009
- 12. Coding Your Tests Quick Poll • How many are using Selenium RC? Friday, 07 August, 2009
- 13. Coding Your Tests How does this help? • We can eliminate duplication by building abstractions • Let’s see an example of this Friday, 07 August, 2009
- 14. Demo Friday, 07 August, 2009
- 15. Coding Your Tests What happens next? • All commonly used methods get pulled into the base class of all tests • As the test suite grows, so does the base class • Uh oh...the base class starts getting too big Friday, 07 August, 2009
- 16. Coding Your Tests How Big is Too Big? • You can’t tell someone else has already written the code you’re about to write • Frequent version control conflicts • Maintenance is an issue again Friday, 07 August, 2009
- 17. Coding Your Tests How to rein in your base class? • Observation: For any given page, most of the behavior does not apply • Example: you can’t change your password on the “view cart” page • What if we moved the page-specific behavior into a corresponding class? • Voila! The Page Object is born Friday, 07 August, 2009
- 18. The Page Object Friday, 07 August, 2009
- 19. The Page Object What does it do? • Consolidates the code for interacting with any given UI element • Allows you to model the UI in your tests Friday, 07 August, 2009
- 20. The Page Object What does it do? • Exposes methods that reflect the things a user can see and do on that page, e.g. • addItemToCart(), getPrice() • getEntryTitle(), saveDraft(), publishEntry() • Hides the details of telling the browser how to do those things Friday, 07 August, 2009
- 21. Demo Friday, 07 August, 2009
- 22. The Page Object Results • Test code is very readable • No duplication of Selenium API calls • Interactive documentation via Ctrl-Space • Eminently reusable code Friday, 07 August, 2009
- 23. The Page Object Results • This technique is framework-agnostic • Has been used with Selenium, WebDriver (Selenium 2.0), Watir, and others • I’ve even used it to drive desktop apps Friday, 07 August, 2009
- 24. The Page Object Results • Because it encapsulates the details of the test framework API: • You can use this technique to simplify the process of swapping frameworks • In theory, you only need to reimplement the Page base class. Friday, 07 August, 2009
- 25. But wait, there’s more! It gets better! • Page Objects improve maintainability • They also provide an opportunity to make test creation extremely quick (and maybe even fun!) • How? Page Objects + Method Chaining Friday, 07 August, 2009
- 26. Method Chaining What’s method chaining? • Change the signature of user behavior methods so that they return the page object itself • Allows multiple behavior methods to be called in sequence Friday, 07 August, 2009
- 27. Method Chaining What will it do for me? • Removes for “code clutter” • Tests become even more readable Friday, 07 August, 2009
- 28. Method Chaining How does it work in practice? • All Page Object methods return a reference to a Page Object • If the “user action” moves the focus to a different page, the method should return that page object • Otherwise, return the same page object • Time for an example Friday, 07 August, 2009
- 29. Demo Friday, 07 August, 2009
- 30. Method Chaining Results • Test code is even more readable • Very quick to write • (Actually kinda fun. Don’t tell anyone!) Friday, 07 August, 2009
- 31. Method Chaining Caveats • Dependent on tool support • Lots of options: IntelliJ IDEA, Eclipse, NetBeans, VisualStudio Friday, 07 August, 2009
- 32. Method Chaining Caveats • Tool support depends on language • Excellent support for strongly typed languages like Java and C# • Support is “up and coming” for dynamically typed languages (Ruby, Python, and Perl) Friday, 07 August, 2009
- 33. The Page Object Pattern • Technique for organizing test code that: • Promotes reuse and reduces duplication • Makes tests readable • Makes tests more robust (less brittle) • Improves maintainability, particularly if the application is rapidly evolving • Is just as quick record & playback! Friday, 07 August, 2009
- 34. Q &A Friday, 07 August, 2009