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[SOLVED] Why Are Selenium GUI Tests Not Visible on Windows - jenkins?

[SOLVED] Solutions for Making Selenium GUI Tests Visible on Windows in Jenkins

In this article, we look at the common problem of Selenium GUI tests not showing on Windows when we run them through Jenkins. This issue can be annoying for developers and testers. They need automated GUI testing to make sure their applications work right. We will give you a simple guide to fix this problem. We will show different ways to help you run and see your Selenium GUI tests in Jenkins.

Here are the solutions we will talk about to make your Selenium GUI tests visible on Windows in Jenkins:

  • Part 1 - Configure Jenkins to Run in Headless Mode
  • Part 2 - Use Xvfb to Simulate a Display
  • Part 3 - Enable Display Output for Selenium Tests
  • Part 4 - Adjust Jenkins Pipeline for GUI Tests
  • Part 5 - Set Up Remote Desktop Access for Jenkins Agents
  • Part 6 - Verify Selenium WebDriver Configuration

By the end of this article, we hope you understand how to set up Jenkins for Selenium GUI testing on Windows. If you need more help with Jenkins issues, you can check these links: How to Fix Jenkins CI Pipeline and How to Fix Permission Denied Errors. Now, let’s dive in and fix the visibility issue for Selenium GUI tests in Jenkins!

Part 1 - Configure Jenkins to Run in Headless Mode

We want to run Selenium GUI tests on Jenkins in Windows without a visible screen. So, we need to set up Jenkins to work in headless mode. This lets tests run without a graphical user interface. This is very important for CI/CD pipelines.

  1. Set Jenkins to Run in Headless Mode:

    • First, we open the Jenkins configuration file. You can find it at C:\Program Files (x86)\Jenkins\jenkins.xml.

    • Next, we add this line in the <arguments> tag:

      -Djava.awt.headless=true

  2. Start Jenkins as a Windows Service:

    • Now, we open the Command Prompt as an administrator.

    • We use this command to start Jenkins:

      java -jar jenkins.war --httpPort=8080

  3. Update Selenium WebDriver:

    • We need to make sure we are using a headless browser driver. If we use Chrome, it looks like this:

      ChromeOptions options = new ChromeOptions();
options.addArguments("--headless");
options.addArguments("--disable-gpu");
options.addArguments("--window-size=1920x1080");
WebDriver driver = new ChromeDriver(options);

  4. Use Jenkins Pipeline:

    • In our Jenkinsfile, we should say to use headless mode for the Selenium tests:

      pipeline {
    agent any
    stages {
        stage('Run Tests') {
            steps {
                script {
                    // Put your test command here
                    sh 'mvn test -Dheadless=true'
                }
            }
        }
    }
}

When we configure Jenkins to run in headless mode, we can run Selenium GUI tests well on Windows. We do not need a visible screen. If we have any trouble with Jenkins pipeline, we can check this Jenkins CI pipeline fix article.

Part 2 - Use Xvfb to Simulate a Display

We can run Selenium GUI tests on Jenkins in a headless environment by using Xvfb (X Virtual Framebuffer). This helps our tests that need a graphical interface to run without needing a real display.

Steps to Configure Xvfb:

  1. Install Xvfb: First, we need to make sure that Xvfb is installed on our Jenkins server. We can use the package manager to install it.

    For Ubuntu or Debian, we use:

    sudo apt-get install xvfb

    For CentOS or RHEL, the command is:

    sudo yum install xorg-x11-server-Xvfb

  2. Start Xvfb in Jenkins Pipeline: Next, we can start Xvfb in our Jenkins pipeline script. Here is an example of how we can do this:

    pipeline {
    agent any
    stages {
        stage('Run Tests') {
            steps {
                script {
                    // Start Xvfb
                    sh 'Xvfb :99 -screen 0 1920x1080x24 &'
                    // Set display environment variable
                    env.DISPLAY = ':99'

                    // Run your Selenium tests here
                    sh 'your-selenium-test-command'
                }
            }
        }
    }
}

  3. Verify Installation: We need to check if Xvfb is running correctly. We can do this by looking at the process list:

    ps aux | grep Xvfb

  4. Environment Variables: It is important to set the right environment variables in our Jenkins configuration or pipeline. We need to set the DISPLAY variable. This helps Selenium know where to show its GUI.

By following these steps to use Xvfb for simulating a display, we can run our Selenium GUI tests on Jenkins without any visible GUI issues. If we have any problems, we can check this guide on fixing Jenkins CI pipeline issues for more help.

Part 3 - Enable Display Output for Selenium Tests

We need to make sure our Selenium GUI tests can show output on Windows when using Jenkins. To do this, we have to enable display output. We can do this by setting the right properties and using tools like Selenium Grid or RemoteWebDriver with a display server.

  1. Set Display Environment Variables: We will change our Jenkins job settings to include environment variables. This will tell Selenium where to show the output. We can add this to our Jenkins pipeline script:

    environment {
    DISPLAY = ':99'  // We assume we are using Xvfb or something similar
}

  2. Use RemoteWebDriver: If we are running tests on another machine, we should use RemoteWebDriver to connect to our Selenium server. We need to make sure we use the correct URL and settings.

    DesiredCapabilities capabilities = DesiredCapabilities.chrome();
capabilities.setCapability("enableVNC", true); // Turn on VNC for display
WebDriver driver = new RemoteWebDriver(new URL("http://<selenium-server>:4444/wd/hub"), capabilities);

  3. Add Logging to Tests: To keep track of what happens in our tests, we should add logging in our Selenium test scripts. We can use tools like Log4j or SLF4J.

    Logger logger = Logger.getLogger("SeleniumTests");
logger.info("Starting test case...");

  4. Capture Screenshot on Failure: To help us see what went wrong, we can take screenshots when a test fails. This can help us find visibility problems.

    File screenshot = ((TakesScreenshot) driver).getScreenshotAs(OutputType.FILE);
FileUtils.copyFile(screenshot, new File("screenshots/test-failure.png"));

  5. Configure Jenkins Console Output: We need to make sure our Jenkins job can capture and show console output. We go to the job settings and check the option to “Capture Console Output”.

When we enable display output for Selenium tests in Jenkins, we can troubleshoot GUI problems that come up during automated testing. For more details on Jenkins settings, you can look at this guide.

Part 4 - Adjust Jenkins Pipeline for GUI Tests

We need to make sure our Jenkins pipeline is set up right for running Selenium GUI tests. We can do this by changing our Jenkinsfile. Here’s how we can do it:

  1. Use the Headless Browser: We need to change our testing scripts so they run in headless mode. We can do this by adding some browser options in our WebDriver code:

    import org.openqa.selenium.chrome.ChromeOptions;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.chrome.ChromeDriver;

ChromeOptions options = new ChromeOptions();
options.addArguments("--headless");
options.addArguments("--disable-gpu");
WebDriver driver = new ChromeDriver(options);

  2. Update Jenkinsfile: We should make sure our Jenkinsfile shows the right settings. Here is an example snippet:

    pipeline {
    agent any
    stages {
        stage('Build') {
            steps {
                // Build steps
            }
        }
        stage('Test') {
            steps {
                script {
                    // Run Selenium tests
                    sh 'mvn clean test'
                }
            }
        }
    }
}

  3. Set Environment Variables: If our tests need environment variables, we should set them in our Jenkinsfile:

    environment {
    DISPLAY = ':99'
}

  4. Execute with Xvfb: If we have tests that need a display, we must include Xvfb in our pipeline:

    stage('Test with Xvfb') {
    steps {
        script {
            sh 'Xvfb :99 -screen 0 1920x1080x24 &'
            sh 'mvn clean test'
        }
    }
}

  5. Check for Dependencies: We need to make sure all dependencies are listed in our pom.xml for Maven projects. This will help us avoid problems while building.

By adding these settings in our Jenkins pipeline, we can run Selenium GUI tests well. For more details on Jenkins pipeline setup, we can check this guide.

Part 5 - Set Up Remote Desktop Access for Jenkins Agents

We can enable Selenium GUI tests to run on Jenkins agents in Windows by setting up Remote Desktop Access. This lets us see and interact with the Jenkins agent’s desktop. This way, we can make sure the GUI tests run well. Here are the steps to follow:

  1. Install Remote Desktop:

    • First, we need to make sure Remote Desktop is on in the Jenkins agent machine:
      • Right-click on ‘This PC’ and choose ‘Properties’. Then click on ‘Remote settings’.
      • In the Remote Desktop section, we select “Allow remote connections to this computer”.

  2. Configure Jenkins Agent:

    • We need to check that the Jenkins agent runs under a user account that can use Remote Desktop.
    • We add the Jenkins agent to the list of users who can use Remote Desktop.

  3. Use the Correct Display Configuration:

    • For GUI tests, the Jenkins agent should use the desktop environment. If we start Jenkins as a service, we may need to set it to run in a session with a visible display.
    • We can use tools like NSSM (Non-Sucking Service Manager) to run Jenkins as a foreground application.

  4. Remote Desktop Connection:

    • We will use Remote Desktop Connection (mstsc) from our local machine:

      mstsc /v:<Jenkins_Agent_IP>

    • Here, we replace <Jenkins_Agent_IP> with the real IP address of our Jenkins agent.

  5. Verify Display Output:

    • When we connect, we should check that we can see the desktop and that GUI applications can start without problems.

  6. Run Your Selenium Tests:

    • Now we can trigger our Selenium tests in Jenkins while connected through Remote Desktop. This helps to see what happens during the execution.

By setting up Remote Desktop Access for Jenkins agents, we can fix visibility problems with Selenium GUI tests on Windows. If we face issues, we can look for help with common Jenkins problems like how to fix error input device or how to fix permission denied.

Part 6 - Verify Selenium WebDriver Configuration

To make sure our Selenium GUI tests work well on Jenkins, we need to check the Selenium WebDriver configuration. Let’s follow these simple steps to confirm that our setup is right.

  1. Check Selenium WebDriver Version: We need to use a version of Selenium WebDriver that works with our browser. We can check the version in our pom.xml file (for Maven projects) or in our dependency file.

    <dependency>
    <groupId>org.seleniumhq.selenium</groupId>
    <artifactId>selenium-java</artifactId>
    <version>4.0.0</version> <!-- Make sure this matches our browser version -->
</dependency>

  2. Browser Driver Installation: We have to install the right browser driver and make it accessible in our system’s PATH. For example, for Chrome, we should download ChromeDriver and add it to our PATH.

    # Example for adding ChromeDriver to PATH on Windows
set PATH=%PATH%;C:\path\to\chromedriver

  3. Configure WebDriver in Tests: In our test setup, we need to set up the WebDriver correctly. Here’s how we do it for Chrome:

    System.setProperty("webdriver.chrome.driver", "path/to/chromedriver");
WebDriver driver = new ChromeDriver();

  4. Jenkins Environment Variables: We must ensure that Jenkins uses the right environment variables that point to the WebDriver files. We can set them in Jenkins by going to “Manage Jenkins” > “Configure System”.

    • We can add environment variables like WEBDRIVER_CHROME_DRIVER with the path to our ChromeDriver.

  5. Run Tests in Jenkins: We should run our tests using a Jenkins job. Let’s check that the Jenkins job configuration has the right paths and settings.

    pipeline {
    agent any
    stages {
        stage('Test') {
            steps {
                script {
                    // Run our Selenium tests
                    sh 'mvn clean test'
                }
            }
        }
    }
}

  6. Check Jenkins Logs: After we run the tests, we should look at the Jenkins build logs for any errors related to the WebDriver. If we see issues, it may mean there is a misconfiguration or a missing part.

For more help with fixing problems, we can check the section on fixing Jenkins CI pipeline errors. It is very important to verify the Selenium WebDriver configuration. This helps us make sure our Selenium GUI tests run successfully on Jenkins.

Frequently Asked Questions

1. Why are my Selenium GUI tests not showing in Jenkins on Windows?

If we can’t see our Selenium GUI tests in Jenkins on Windows, it may be because there is no graphical user interface when we run the tests. We can run Jenkins in headless mode or use Xvfb to create a display environment. For more steps on how to do this, check our guide on how to turn off Sonar for Jenkins.

2. How can I run Jenkins in headless mode for Selenium tests?

To run Jenkins in headless mode, we need to set up the Jenkins server to work without a graphical environment. We can do this by changing the Jenkins startup settings to add headless options. For more info on setting up Jenkins well, look at our article on fixing Jenkins CI pipeline issues.

3. What is Xvfb and how does it help with Selenium tests in Jenkins?

Xvfb stands for X Virtual Framebuffer. It is a display server that does all graphical work in memory without showing anything on screen. This is very important for running Selenium GUI tests in Jenkins when we don’t have a physical display. For more details about Xvfb, our resources on choosing between Hudson and Jenkins can help.

4. How do I enable display output for Selenium tests in Jenkins?

To see display output for Selenium tests in Jenkins, we must make sure our testing framework is set to show logs. This usually means we need to set the right logging level and make sure Jenkins captures console output. If we have problems, we can check our guide on fixing permission denied errors in Jenkins.

5. Can I set up remote desktop access for Jenkins agents running Selenium tests?

Yes, we can set up remote desktop access to Jenkins agents that run our Selenium tests. This lets us watch and interact with the tests while they run. For detailed steps on how to set up remote access, look at our article on setting environment variables in Jenkins.

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