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![“Selenium is not unstable, and your tests
don’t need to be flaky. […] When your tests
are flaky, do some root cause analysis to
understand why they’re flaky. It’s very
seldom because you’ve uncovered a bug in
the test framework.”
-Simon Stewart, Google Testing Blog 2009, “My Selenium Tests Aren't
Stable!”](https://image.slidesharecdn.com/refactoringpageobjects-thescreenplaypattern201611-170112134645/85/Refactoring-page-objects-The-Screenplay-Pattern-14-320.jpg)
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Refactoring page objects The Screenplay Pattern
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- 2. @AntonyMarcano riverglide.com Contributions, quotations &references in: 2
- 3. All code is… Seriously Hindered In Testing? Inspiredby Simon Stewart’s opening keynote at Selenium Conf 2016…
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- 5. All code is… Seriously Hindered In Translation? Inspiredby Simon Stewart’s opening keynote at Selenium Conf 2016…
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- 7. All code is… Seriously Hindered In Transformation? Inspiredby Simon Stewart’s opening keynote at Selenium Conf 2016…
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- 9. Just enough togive confidence that the product hangs together for the key usage examples DON’T try to prove that absolutely everything works together in absolutely every way that the whole product is supposed to
- 10. The Screenplay patternis as a way of separating any kind of interactions with your product, including RESTful APIs, Web or any form of interaction. For the purposes of this talk, we’re going to focus on page objects…
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- 12. Support code usingPage Objects Todo List Page newTodo todoItems todosRemaining toggleAllButton clearCompletedButton filterTodos … addATodoItem() addTodoItems() toggleAllCompleted() filterItems() … Responsibilities How to find page elements How a user completes given tasks
- 13. Let’s go backin time…
- 14. “Selenium is notunstable, and your tests don’t need to be flaky. […] When your tests are flaky, do some root cause analysis to understand why they’re flaky. It’s very seldom because you’ve uncovered a bug in the test framework.” -Simon Stewart, Google Testing Blog 2009, “My Selenium Tests Aren't Stable!”
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- 17. What’s wrong withthis?
- 18. “A code smellis a surface indication that usually corresponds to a deeper problem in the system. The term was first coined by Kent Beck while helping me with my Refactoring book.” -Martin Fowler
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- 20. What can helpus refactor to a better design?
- 21. SOLID Single Responsibility Principle OpenClosed Principle Liskov Substitution Principle Interface Segregation Principle Dependency Inversion Principle
- 22. Let’s focus on… SingleResponsibility Principle Open Closed Principle
- 23. Single Responsibility Principle “Ifa class has more than one responsibility, then the responsibilities become coupled. Changes to one responsibility may impair or inhibit the class’ ability to meet the others. This kind of coupling leads to fragile designs that break in unexpected ways when changed.” -Robert Martin, Agile Principles, Patterns & Practices
- 24. Open Closed Principle TheOpen Closed Principle (coined by Bertrand Meyer in Object-Oriented Software Construction) states that a class should be open for extension, but closed for modification. This means that it should be possible to extend behaviour by writing a new class without changing existing, working code.
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- 26. Todo List Page newTodo todoItems todosRemaining toggleAllButton clearCompletedButton filterTodos … addATodoItem() addTodoItems() toggleAllCompleted() filterItems() … Responsibilities Howto find page elements How a user completes given tasks
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- 28. Todo List Page newTodo todoItems todosRemaining toggleAllButton clearCompletedButton filterTodos … addATodoItem() addTodoItems() toggleAllCompleted() filterItems() … AddNewTodo newTodo addTodoItem() addTodoItems() MaintainTodos toggleAllButton clearCompletedButton toggleAllCompleted() clearAllCompletedTodos() Extract Class Extract Class
- 29. Todo List Page newTodo todoItems todosRemaining toggleAllButton clearCompletedButton filterTodos … addATodoItem() addTodoItems() toggleAllCompleted() filterItems() … TodoListPage newTodo todoItems todosRemaining toggleAllButton clearCompletedButton filterTodos … AddATodoItem perform() ExtractClass Replace Method with Method Object AddTodoItems perform() ToggleAllCompleted perform()
- 30. What are wemodeling?
- 32. Modelling the problem Notthe solution
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- 35. There are actors. Actorshave abilities.
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- 38. Things we interactwith are just data
- 39. Instead of afew large classes, you have more smaller classes. When you identify a new task an actor must perform, just add a new task class.
- 40. You don’t haveto use cucumber for this either… Example using Screenplay implementation in Serenity-BDD
- 41. Your scenario isa narrative for a cast of actors, each playing a different role. Each actor has the task of performing action to the best of their ability…
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- 44. Before you begin Don’taim to refactor all of your support code. Try an experiment alongside what you have. See how it feels and if you like it, look at how to use the approach with new scenarios.
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- 46. • As anysupport code grows, ask first “are we testing too much here?” • Big classes with interaction methods (like PageObjects) are useful as training wheels • As we try to go faster, training wheels make us less stable • The Screenplay Pattern allows us to ride more safely, at speed, from the start
- 47. Links Full article: bit.ly/rg-screenplay Exampleson Github: bit.ly/rg-serenity-eg using Serenity Acknowledgements Andy Palmer John Ferguson Smart & Jan Molak
- 48. Contact: antony@riverglide.com http://antonymarcano.com/blog @AntonyMarcano Materials createdwith the time, love and attention of Antony Marcano and Andy Palmer