Automation Abstraction Layers: Page Objects and Beyond

1
Automation Abstractions:
Page Objects and Beyond
Alan Richardson
@eviltester
https://xp-dev.com/svn/AutomationAbstractions
www.SeleniumSimplified.com
www.EvilTester.com
www.CompendiumDev.co.uk
www.JavaForTesters.com

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What is Abstraction?
● Modelling
● Separation of concerns
● Logical vs Physical
● Functional vs Structural
● Interfaces vs Implementations
● Data / Entities / Persistence
● Functionality / Task Flow
● Goals / Strategies
● Layers – GUI, DB, HTTP
● Etc.

“I must create a system. or be
enslav'd by another Mans; I
will not reason & compare:
my business is to create”
William Blake, 1820
Jerusalem: The Emanation of the Giant Albion
3
http://www.blakearchive.org/exist/blake/archive/object.xq?objectid=jerusalem.e.illbk.10&java=no

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Example Test Without
Abstraction
@Before
public void startDriver(){
@Test
public void canCreateAToDoWithNoAbstraction(){
driver.get("http://todomvc.com/architecture-examples/backbone/");
int originalNumberOfTodos = driver.findElements(
By.cssSelector("ul#todo-list li")).size();
WebElement createTodo = driver.findElement(By.id("new-todo"));
createTodo.click();
createTodo.sendKeys("new task");
createTodo.sendKeys(Keys.ENTER);
assertThat(driver.findElement(
By.id("filters")).isDisplayed(), is(true));
int newToDos = driver.findElements(
assertThat(newToDos, greaterThan(originalNumberOfTodos));
}
driver = new FirefoxDriver();
}
@After
public void stopDriver(){
driver.close();
driver.quit();
}
NoAbstractionTest.java

But this does use some
abstraction layers
LLooccaattoorr A Abbssttrraaccttioionns
WebElement Generic Element Abstraction
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Example Test Without
Abstraction
@Before
WebDriver Generic Browser Abstraction
@Test
public void canCreateAToDoWithNoAbstraction(){
Firefox Browser Abstraction
driver.get("http://todomvc.com/architecture-examples/backbone/");
int originalNumberOfTodos = driver.findElements(
WebElement createTodo = driver.findElement(By.id("new-todo"));
createTodo.click();
createTodo.sendKeys("new task");
createTodo.sendKeys(Keys.ENTER);
By.id("filters")).isDisplayed(), is(true));
int newToDos = driver.findElements(
Manipulation Abstractions
assertThat(newToDos, greaterThan(originalNumberOfTodos));
}
}
@After
driver.close();
driver.quit();
}

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WebDriver provides abstractions
● Browser
● DOM
● Web Element
Tool vendors gain value from generic abstractions.
You gain value from 'domain' abstractions.

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Example Test With Abstraction
@Before
@Test
public void canCreateAToDoWithAbstraction(){
TodoMVCUser user =
new TodoMVCUser(driver, new TodoMVCSite());
user.opensApplication().and().createNewToDo("new task");
ApplicationPageFunctional page =
new ApplicationPageFunctional(driver,
new TodoMVCSite());
assertThat(page.getCountOfTodoDoItems(), is(1));
assertThat(page.isFooterVisible(), is(true));
}
}
@After
driver.close();
driver.quit();
}

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Why Abstraction?
● Change implementations
● Single Responsibility – only changes when
necessary
● Makes automation readable and maintainable
● We can unit test some of our test code
● etc.

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Some Abstraction Layer Categories
1) Data
– Generic Data Abstractions e.g. email, postcode
2) Physical
– Physical layout of your application e.g. pages,
components
– Navigation across pages
3) Domain
– Your application Entities domain e.g. user, account
4) Logical
– User actions, workflows

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Common Automation Abstractions
● Page Objects: pages, components, widgets
● Dom Element Abstractions: select, textbox, etc.
● Domain Objects: user, account, order
● Gherkin (Given/When/And/Then)
● Domain Specific Languages: code, keywords
● ...

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Abstraction != Implementation
● Abstraction != Tool / Framework /
Implementation
● Gherkin != Cucumber
● Page Object != Page Factory / Slow Loadable
● DSL != Keyword Driven
If we want to get good at abstraction then we
need to model, split apart, make the relationships
clear, and be aware of our options.

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Page Objects
● The most obvious
automation abstraction
● What is it?
– A page? A Component?
● Do web applications still
have pages?

A Page Object that abstracts a Page
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● Often has methods for
– Opening the page
– Accessing elements
– Doing stuff, and navigating as a side-effect
– Logical high level functionality e.g. login
– Low level physical functionality e.g.
typeUsername, clickLoginButton
Should a Page Object be responsible for all of
this?

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Page Object Design Decisions
● What methods does it have?
– Functional
● login(username, password),
● loginAs(user)
– Structural
● enterName(username), enterPassword(password),
clickLogin(), submitLoginForm(username, password)
● Does it expose elements or not?
– public WebElement loginButton;
– public WebElement getLoginButton();
– public clickLoginButton();

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Page Object Functionality
Approaches
● Expose WebElements Directly
– Leads to WebElement Abstractions
– public TextField userNameField;
● Hide WebElements behind physical functional
methods e.g. typeUserName("bob");
● Logical helper methods e.g.
loginAs(name,pass)
● Layers of Page Objects
– Physical
– Logical

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Navigation Design Decisions
● Does a Page Object return other pages?
public IssueListPage submit(){
driver.findElement(By.id(“submit”)).click();
return new IssueListPage(driver);
}
● Or Navigate implicitly after interactions
● Or have navigation objects

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Implicit or Explicit Wait?
● Implicit Wait
driver.manage().timeouts().
implicitlyWait(15L, TimeUnit.SECONDS);
By.id("filters")).isDisplayed()
, is(true));
● Explicit Wait
driver.manage().timeouts().
implicitlyWait(0L, TimeUnit.SECONDS);
WebDriverWait wait = new WebDriverWait(driver,15);
wait.until(ExpectedConditions.elementToBeClickable
(By.id("filters")));
Example: 'NoAbstractionTest.java'

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Implementing Page Objects
● POJO
– Plain object, driver in constructor, methods use
driver.<method>
● Page Factory
– Annotated elements, lazy instantiation via reflection
● LoadableComponent
– Common interface (load, isLoaded), isLoaded
throws Error
● SlowLoadableComponent
– Common interface, waits for on isLoaded
● Other approaches?

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Example Implementations

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POJO
● 'ApplicationPage.java'
– Used in 'SequentialCreationOfTest.java'
– Not much refactoring in the example
● Simple Class
● WebDriver passed to constructor
● Composition of any components
● e.g.
– com.seleniumsimplified.todomvc.page.pojo
– 'ApplicationPage.java'
● Not much refactoring in the example

22
Functional vs Structural
● Functional
– loginAs(username, password)
● Structural
– enterUsername
– enterPassword
– clickLoginButton
– submitLoginForm(username, password)

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Functional Vs Structural Example
● One way of answering “what methods to put on
a page object”
– Is it functional / behavioural?
– Is it structural / Physical?
● Functional 'uses' Structural implementation
● Why?
– Sometimes it is just a naming difference
– Handling exceptions in functional but not structural
– Higher level methods in Functional
– Different concepts e.g. deleteLastItem

24
Page Factory
● Annotate fields with @FindBy
● Instantiate in constructor using
PageFactory.initElements
– Can create your own page factory initialiser
● Avoids boilerplate accessor methods
● Fast to create Page Objects
● Might become harder to expand and maintain

25
Page Factory Example
@FindBy(how = How.CSS, using="#todo-count strong")
private WebElement countElementStrong;
@FindBy(how = How.CSS, using="#todo-count")
private WebElement countElement;
@FindBy(how = How.CSS, using="#filters li a")
List<WebElement> filters;
@FindBy(how = How.ID, using="clear-completed")
List<WebElement> clearCompletedAsList;
@FindBy(how = How.ID, using="clear-completed")
WebElement clearCompletedButton;
public ApplicationPageStructuralFactory(WebDriver driver, TodoMVCSite todoMVCSite)
{
PageFactory.initElements(driver, this);
this.driver = driver;
...

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SlowLoadableComponent
● Some pages and components need
synchronisation to wait till they are ready
– One approach – SlowLoadableComponent adds
responsibility for waiting, to the page
● extend SlowLoadableComponent
● Standard interface for synchronisation on load
– get()
● If isLoaded then return this Else load
● While not loaded{ wait for 200 millseconds}
– Implement load and isLoaded

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Fluent Page Objects
todoMVC = new ApplicationPageFunctionalFluent(
driver, todoMVCSite);
todoMVC.get();
todoMVC.enterNewToDo("First Completed Item").
and().
toggleCompletionOfLastItem().
then().
enterNewToDo("Still to do this").
and().
enterNewToDo("Still to do this too").
then().
filterOnCompleted();

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Fluent Page Objects
● Methods return the page object or other objects
instead of void
– void clickDeleteButton();
– PageObject clickDeleteButton();
● Syntactic sugar methods:
– and(), then(), also()
● Can work well at high levels of abstraction and
when no navigation involved
● Train Wreck?

Navigation Options
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● Direct in Test: page.get(); page.waitFor();
● Instantiate new pages based on test flow
– Navigation as side-effect, may have to bypass 'get'
– Loadable pages, non-loadable, support classes
● Page Object methods might return other Pages
– e.g. a method on the login page might be
● MyAccountPage clickLogin();
● We might use navigation objects
– direct, Jump.to(MyAccountPage.class)
– path based (current page → desired page)
● Navigate.to(MyAccountPage.class)

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Possible Domain Abstractions
● Logical Objects
– ToDo
– ToDoList
● Physical Objects
– LocallyStoredToDo
● Actors
– User
● Environment
– Site
– Implementation

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Page Objects & Domain Objects
● Instead of
– todoMVC.enterNewToDo(“New Item”)
● We could have have
– ToDoItem newItem = new ToDoItem(“New Item”);
– todoMVC.enterNewToDo(newItem);
● See code in DomainBasedTest

32
Domain Objects That Span Logical
& Physical
e.g. User
● user.createNewToDo(“new item”)
● user.createNewToDo(newItem)
● See use in NoAbstractionTest

33
Sometimes it is possible to over
think this stuff
● Don't let thinking about this slow you down
● Conduct experiments
● Refactor
● Rethink if
– you are maintaining too much
– your abstraction layer stops you doing stuff
– you are 'working around' your abstraction layers

35
Element Abstraction Example
public interface Checkbox {
public boolean isChecked();
public Checkbox check();
public Checkbox uncheck();
public Checkbox toggle();
}
● Would you include 'toggle'?

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Element Abstractions
● Existing support classes: Select,
● Possible: TextBox, Checkbox, TextBox, File etc.
● Can enforce Semantics
– Checkbox: isChecked, check(), uncheck(), toggle()
– TextBox: clear(), enterText()
– etc.
● Pass back from Page Objects into test?

Element Abstraction Pros and Cons
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● May have to create a custom page factory
● Can help 'restrict' code i.e. check or uncheck,
rather than click, enforces 'semantics'
● If you create them...
– allow return WebElement
● so that I can go beyond the abstraction layer if I need to.
Not required if it is just a WebElement wrapper.

38
Component Abstractions
● Shared Components/Widgets on the page
● e.g.
– VisibleToDoEntry, VisibleToDoList
– Filters, Footer, Header, etc.
● Could have 'functional' representation for
repeated items e.g. login forms
● Could have 'structural' representation
● Likely use : page object composition

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Component Abstraction Example
TodoEntry todo = page.getToDoEntryAt(lastItemPosition);
todo.markCompleted();
Instead of
page.markTodoCompleted(lastItemPosition);

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Gherkin as an abstraction layer
Feature: We can create and edit To Do lists in ToDoMvc
We want to amend todos in ToDoMVC because that is
the set of exercises on the abstraction tutorial
Scenario: Create a ToDo Item
Given a user opens a blank ToDoMVC page
When the user creates a todo "new task"
Then they see 1 todo item on the page
● Implement steps using highest appropriate
abstraction layer
● CucumberJVM as 'DSL implementor'
● 'Expressibility' vs 'Step Re-use'
● See todomvc.feature and ToDoMvcSteps

41
My modeling biases
● Driver
– Inject so instantiate any page or component as
required/desired at any time
● Explicit Synchronisation
– To make sure that the desired object is available
and ready for use (as defined by synchronisation)
● Navigation
– Implicit (via taking action e.g. click)
– Explicit Navigation Object, not in page object
● Open/jump (via driver.get)
● To (state model from current, to desired)

42
My modeling biases
● Page Objects
– Physical
● abstract the 'real world'
– Components
● For common features on the page
– Logical
● abstract the functionality
● Sometimes these are entity methods not page objects
– e.g. user.registers().and().logsin()
● I tend not to....
– abstract WebElements

43
My modeling biases
● I tend not to....
– abstract WebElements
– Use inheritence to create a model of the app
● e.g. MyAppPage extends GenericAppPage
– Use 3rd party abstractions on top of WebDriver

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Are there rights and wrongs?
● Right / Wrong?
● Decisions?
● Project/Team/Organisation Standards?
Identify your own biases -
Experiment
Recognise your decisions

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Decisions
● The 'limits' and overlap of Abstraction Layers
● Build it now, or 'refactor to' later
● How much change is anticipated?
– To which layer? GUI, Business domain, Workflow?
● Who is working with the automation code?
– Skill levels? Support needed?
● How/When with the automation execute?

46
Other Useful Links
● Jeff “Cheezy” Morgan – page-object ruby gem,
data_magic gem and stareast code
– https://github.com/cheezy?tab=repositories
● Marcus Merrell
– Self-Generating Test Artifacts for Selenium/WebDriver
– https://www.youtube.com/watch?v=mSCFsUOgPpw
● Anand Ramdeo
– One Step at a Time
– https://www.youtube.com/watch?v=dFPgzH_XP1I

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Homework
● Using the code at
https://xp-dev.com/svn/AutomationAbstractions/
– Compare the different implementations under 'main'
● com.seleniumsimplified.todomvc.page
– Investigate how the Page Objects delegate to each
other, and the Domain Objects use Page Objects
– Examine the 'test' usage of the Page Objects and
Domain Objects
– Examine the different navigation approaches

48
Blogs and Websites
● CompendiumDev.co.uk
● SeleniumSimplified.com
● EvilTester.com
● JavaForTesters.com
● Twitter: @eviltester
Online Training Courses
● Technical Web Testing 101
Unow.be/at/techwebtest101
● Intro to Selenium
Unow.be/at/startwebdriver
● Selenium 2 WebDriver API
Unow.be/at/webdriverapi
Videos
youtube.com/user/EviltesterVideos
Books
Selenium Simplified
Unow.be/rc/selsimp
Java For Testers
leanpub.com/javaForTesters
Alan Richardson
uk.linkedin.com/in/eviltester
Independent Test Consultant
& Custom Training
Contact Alan
http://compendiumdev.co.uk/contact

Automation Abstraction Layers: Page Objects and Beyond

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