What are the steps to execute Selenium WebDriver tests (Maven project) on a virtual server via Jenkins using a headless browser?

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1

I have a Maven project that runs successfully on my local machine using the command mvn clean install exec:java. Below is my Pom.xml setup for the project. I have established a ‘GIT repository’ in sync with the ‘Jenkins Job’. In Jenkins, I have configured a job with the following specifications:

  • JDK 7
  • Xvfb configuration (I need additional details on this setup)
  • Maven command: mvn clean install exec:java.

I am attempting to execute this Maven project (Selenium tests) on a separate server. However, I’m encountering the following error when running the project:

org.openqa.selenium.NoSuchElementException: Element not found: {"method":"id","selector":"mcHeaderLink"}

Could you help me understand why this error occurs and how I might resolve it?

2

Running Selenium WebDriver tests with Jenkins using a headless browser on a virtual server involves several steps to ensure everything is configured properly. Here’s a streamlined approach to diagnose and resolve the NoSuchElementException issue:

  1. Confirm Element Existence: First, ensure the element with id="mcHeaderLink" is correctly available in the page's HTML. Use browser developer tools on the test environment to verify.
  2. Headless Execution: Since you’re running tests in a headless mode, verify that your selectors are valid. Render issues sometimes occur when switching from UI to headless.
  3. Set Up Xvfb: For Xvfb configuration on your server, adjust the following in Jenkins: 
    Xvfb auto-start: true
Display name: :99
Additional options: -screen 0 1920x1080x24
    Ensure the Xvfb plugin is installed and the settings match the display requirements of your test environment.
  4. Edit POM and Code Base:
    • Ensure the selenium-htmlunit-driver or similar is added for headless execution via Maven dependencies.
    • Modify your WebDriver setup in the tests: 
      ChromeOptions options = new ChromeOptions();
options.addArguments("--headless");
new ChromeDriver(options);
  5. Debugging: Add extensive logging within your Selenium scripts to catch page load issues or delayed response causing the element not to appear promptly.
  6. Jenkins Pipeline: Within Jenkins, ensure your job workspace is clean before each build by enabling Delete workspace before build starts.

After implementing these adjustments, rerun your Jenkins job. This should address most issues related to element visibility in headless environments.

3

To address the NoSuchElementException in your Selenium tests running on a headless browser via Jenkins, consider the following steps, which may offer a different perspective from previously provided solutions:

  1. Verify Element Visibility Conditions: Ensure that the element you're targeting is visible at the point your Selenium script tries to access it. Introduce explicit waits which are particularly useful in headless mode, where load timing might differ: 
    WebDriverWait wait = new WebDriverWait(driver, Duration.ofSeconds(10));
WebElement element = wait.until(ExpectedConditions.visibilityOfElementLocated(By.id("mcHeaderLink")));
  2. Ensure Correct Page State: Double-check that the page is in the expected state for the element to be present. This includes checking for any modal dialogs, alerts, or pop-ups that might block elements from being found.
  3. Adjust Xvfb Further: If Xvfb configuration might not be aligning fully with what's needed, consider tweaking the screen size and depth further to ensure compatibility: 
    Xvfb auto-start: true
Display name: :99
Additional options: -screen 0 1280x1024x24
  4. Use Headless Browser Debugging Tools: Utilize debugging tools specifically designed for headless browsers, like recording a test run to see exactly what is happening, which can help confirm the element's presence: 
    options.addArguments("--remote-debugging-port=9222");
  5. Parallel Execution Considerations: If tests run concurrently on the server, ensure that system resources are not being maxed out, which may affect element visibility and timing.
  6. Check Build Environment: Ensure that the server has all necessary dependencies and environmental configurations similar to your local setup. Sometimes discrepancies arise from library versions or OS differences.

Implementing these strategies should help resolve the issue with element visibility in headless execution. Carefully updating your Selenium scripts and Jenkins configuration can lead to successful automation on your virtual server.