Question

I have been writing Selenium test for web application and there seem to be multiple instances of Internal Server Error in application in case of Internal Server Error, application displays custom error page and and error id is displayed to user to pursue matter with technical team, in case user encounter it.

This makes it a little laborious to debug the test failures during Selenium execution.
I was thinking to use some mechanism to keep polling a page with each step executed in test to find if there was any instance of Internal Server error, And this is when I came across Junit Rule and thought of writing a custom annotation for it, some thing like –

public class SelTestCase {
    protected WebDriver driver;

    @Before
    public void startDriver() {
        driver = new FirefoxDriver();
        driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);
        driver.get("http://www.google.com/");
    }

    @After
    public void closeDriver() {
        driver.quit();
    }
}

public class GoogleSearchTest extends SelTestCase {

    @Rule
    PageChecker pageChecker = new PageChecker();

    @Test
    @CheckPage
    public void testGoogleSearch() {
        GoogleHomePage googleHomePage = PageFactory.initElements(driver,
                GoogleHomePage.class);
        googleHomePage.searchGoogle("Selenium HQ");
        assert driver.getPageSource().contains("seleniumhq") : "Selenium headquarter search failed";
    }
}

SelTestCase class creates instance of WebDriver to execute test, And here is the PageChecker class –

public class PageChecker extends SelTestCase {

    @Retention(RetentionPolicy.RUNTIME)
    @Target({ElementType.METHOD})
    public @interface CheckPage {
        // page check should take place here (Though not sure if it is right place)     
        // like if(driver.getPageSource.contains("Internal Server Error") {throw Exception ("Err")}
    }

}

This is what I am stuck with, how do I proceed with CheckPage annonations?

Answer 1

IMHO there are two solutions to your problems. If the feature is only needed by a small part of your tests, then I would not use a rule. Instead add a single line errorChecker.checkPage(driver) to each tests and implement the check in this method.

If you need it for almost all your tests:

1. Convert SelTestCase to a rule by extending ExternalResource.

   public class WebDriverRule extends ExternalResource {
     public WebDriver driver;
   
     @Override
     protected void before() {
       driver = new FirefoxDriver();
       driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);
       driver.get("http://www.google.com/");
     }
   
     @Override
     protected void after() {
       driver.quit();
     }
   }
   

2. Add the page check code to the rule by extending Verifier.

   public class PageChecker extends Verifier {
     private WebDriverRule webDriverRule;
     private enabled = true;
   
     public PageChecker(WebDriverRule webDriverRule) {
       this.webDriverRule = webDriverRule;
     }
   
     public void disable() {
       this.enabled = false;
     }
   
     @Override
     public void verify() {
       if(enabled && notValid())
         throw new AssertionError("foo");
     }
   
     private boolean notValid() {
       WebDriver driver = webDriverRule.driver;
       //do something with driver
     }
   }
   

3. Use org.junit.rules.RuleChain to control the execution order of the two rules.

   public class GoogleSearchTest {
     private WebDriverRule webDriverRule = new WebDriverRule();
     private PageChecker pageChecker = new PageChecker(webDriverRule);
   
     @Rule
     public RuleChain driverAroundPageChecker
       = RuleChain.outerRule(webDriverRule).around(pageChecker);
   
     @Test
     public void testGoogleSearch() {
       GoogleHomePage googleHomePage = PageFactory.initElements(driver,
           GoogleHomePage.class);
       googleHomePage.searchGoogle("Selenium HQ");
       assert driver.getPageSource().contains("seleniumhq") : "Selenium headquarter search failed";
     }
   
     @Test
     public void testWithouPageCheck() {
       pageChecker.disable();
       //here is your real test
     }
   }