When writing automated acceptance Tests with Tools like Selenium it becomes handy to abstract from the concrete page by using a Pattern like "Window Driver" or "Page Object".

The goal is, that the acceptance tests are written in a domain specific language - without knowing detail about the page markup.

Example 1 - Login Page

Lets say you want to test a login page. You can do this like:

/**
*
* @test
*/
public function canLogin() {
    $this->open('/login');
    $this->type ( 'username', $login );
	$this->type ( 'password', $password );
	$this->clickAndWait ( "//input[@id='submit' and @name='submit' and @value='submit']" );
	$this->assertTextPresent('Username or Password wrong');
	$this->type ( 'username', $login );
	$this->type ( 'password', $password );
	$this->clickAndWait ( "//input[@id='submit' and @name='submit' and @value='submit']" );
	$this->assertTextPresent('Login ok');
}

But better would be something like this:

/**
*
* @test
*/
public function canLogin() {
     $loginPage = new LoginPage($this);
     $loginPage->loginAs('testuser','wrongpassword');
     $this->assertContains('Username or Password wrong', $loginPage->getErrorMessage());
     $loginPage->loginAs('testuser','testpassword');
     $this->assertTrue($loginPage->isLoggedIn());
}

Example2 - Search Page

Lets think of a second example: A search page that shows some results. The search page has a pagination and sort options. We want to test if the pagination and the sorting works.

Using a Page Object for the Search a test could look something like this:

/**
 * @test 
 */
public function articleSearchWorks() {		
	$search = new Acceptance_Driver_SearchPage($this);		
	$search->open('/index.php?id=502');
	
	//check if the searchpage has a pagination
	$this->assertTrue($search->hasPagination());

	//get the first resultitem that is shown:
	$firstResultLink = $search->getResultDetailLink(1);

	//Now click on sorting - to sort for oldest results first
	$search->selectSorting('Oldest');
	$firstResultLinkAfterSort = $search->getResultDetailLink(1);

	//Check that the Results has changed and does not show the same
	$this->assertNotEquals($firstResultLink, $firstResultLinkAfterSort);

	//now click on page 2 in pagination
	$search->gotoPage(2);
	$this->assertEquals('2',$search->getCurrentPage());
	$firstResultLinkOnPage2 = $search->getResultDetailLink(1);

	//Check that the result shown on page 2 is diffrent
	$this->assertNotEquals($firstResultLinkOnPage2, $firstResultLinkAfterSort);
}

The Window Driver (or Page Object) that belongs to the search page can look like this:

class Acceptance_Driver_SearchPage {
	/**
	 * @var TestingFramework_Server_SeleniumTestCase
	 */
	private $testCase;
	
	/**
	 * @param TestingFramework_Server_SeleniumTestCase $testCase
	 */
	public function __construct(TestingFramework_Server_SeleniumTestCase $testCase) {
		$this->testCase = $testCase;
	}
	/**
	 * opens a search page (and verify that this is a search page)
	 * @param string $url
	 */
	public function open($url) {
		$this->testCase->open($url);
		$this->testCase->assertElementPresent('//div[@class="def-resources"]');		
	}
	
	/**
	 * @return boolean
	 */
	public function hasPagination() {
		return $this->testCase->isElementPresent ( '//ul[@class="paginator"]/li[@class="current"]');
	}
	
	/**
	 * returns the detaillink of the result on the specified position
	 * @param integer $pos
	 * @return string
	 */
	public function getResultDetailLink($pos) {
		try {
			return $this->testCase->getAttribute('//ul[@class="article-list"]/li['.$pos.']//a@href');
		}
		catch (Exception $e) {
			throw new Exception('No First Result Found');
		}
	}
	
	/**
	 * @return integer
	 */
	public function getPaginationPageCount() {
		return $this->testCase->getXpathCount('//ul[@class="paginator"]/li');
	}
	
	/**
	 * returns current active page in pagination
	 * @return string
	 */
	public function getCurrentPage() {
		return $this->testCase->getText('//ul[@class="paginator"]/li[@class="current"]');	
	}
	/**
	 * clicks on the pagination
	 * @param integer $page
	 */
	public function gotoPage($page) {
		$this->testCase->clickAndWait('link='.$page);
	}
	
	/**
	 * clicks on the sorting
	 * @param string $name
	 */
	public function selectSorting($name) {
		$this->testCase->clickAndWait('link='.$name);
	}
}

Summary

To summarize:

• Use seperate Classes to abstract from certain pages or windows in your application
• Write Tests using the domain specific language that this objects provide you.
• If the markup or layout changes, you only need to change the PageObject.
• Asserts should happen in the Test (not in the pageobject)
• Selenium gives you useful functions to get the result and use them in your tests, like:
  • getText(<idendifier>)
  • getAttribute(<idendifier>@<attributname>)
  • getXpathCount(<xpath>)
  • getHtmlSource() (to get complete HTML)
  • getCookieByName() ....

I also found a good Google Article about that pattern: code.google.com/p/selenium/wiki/PageObjects

In Verbindung stehende News:

Automatic testing with Selenium - 06-10-09 16:11