Wednesday, October 17, 2012

Embedding screenshots in Cucumber JVM

I was trying to improve our automated test suite and I thought that it could be useful to capture a screenshot of the browser whenever a test fails.
The current Cucumber JVM implementation highly simplifies this task, but the task is not achieved the way I thought, so this is the reason for this post.

Normally you would use a JUnit TestRule to augment all your test cases with a feature to take screenshots, but for Cucumber JVM it's much easier thankfully to the Execution Hooks:

 public class ScreenshotHook {  
     @Autowired  
     private WebDriver driver;
 
     @After  
     public void embedScreenshot(Scenario scenario) {  
         if (scenario.isFailed()) {  
             try {  
                 byte[] screenshot = ((TakesScreenshot) driver).getScreenshotAs(OutputType.BYTES);  
                 scenario.embed(screenshot, "image/png");  
             } catch (WebDriverException wde) {  
                 System.err.println(wde.getMessage());  
             } catch (ClassCastException cce) {  
                 cce.printStackTrace();  
             }  
         }  
     }  
 }  

As you can see I'm injecting the WebDriver instance (I'm using the Cucumber JVM Spring integration) and defining an embedScreenshot method which is annotated with cucumber.annotation.After: this is the important bit because methods annotated as such will be executed after each cucumber scenario.

For sake of completeness I want to tell you there is another hook cucumber.annotation.Before that can be used for things like logging into your application eliminating those repetitive log in steps.

UPDATE: Scenario was ScenarioResult in pre 1.0.0 versions of Cucumber JVM.

6 comments:

Garen said...

thanks. one correction i made to make this work.

// embed method require byte InputStream
scenario.embed(new ByteArrayInputStream(screenshot), "image/png");

NocturnalSteve said...

I get red errors in my IDE for these parts of the code

@AutoWired

.isFailed

.embed

Am I missing an import?

Rhythm Cloud said...

@nocturnalsteve

For @Autowired
You'll need spring for that

As for the other things,
did you import cucumber.api.Scenario ?

whenthedanceisthrough said...

@garen: How strange...I can't find any reference to scenario.embed ever having accepted a ByteArrayInputStream. http://grepcode.com/file/repo1.maven.org/maven2/info.cukes/cucumber-core/1.2.2/cucumber/api/Scenario.java

Anoop Philip said...

Thanks for this helpful article, can you please help me to set this working in Jenkins job?

paha said...

Hi what about if a you'd like to take a screen Shoot after each step, dou you have ana idea