Screenshot attachment on failure in Selenium Java - Build an Automation Script

Capture screenshot when test fails

Preconditions (3)

Step 1: Open the browser and navigate to 'https://example.com/login'

Step 2: Enter 'wronguser' in the username field

Step 3: Enter 'wrongpass' in the password field

Step 4: Click the login button

Step 5: Verify that the login failed by checking the error message is displayed

Step 6: If the verification fails, capture a screenshot and save it to 'screenshots' folder

✅ Expected Result: On test failure, a screenshot image file is saved with a timestamped filename in the 'screenshots' folder

Automation Requirements - TestNG with Selenium WebDriver

Assertions Needed:

Assert that the error message element is displayed after login attempt

Best Practices:

Use @AfterMethod to capture screenshot on failure

Use explicit waits to wait for elements

Use descriptive file names with timestamps for screenshots

Use Page Object Model for element locators (optional but recommended)

Automated Solution

Selenium Java

import org.openqa.selenium.By;
import org.openqa.selenium.OutputType;
import org.openqa.selenium.TakesScreenshot;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.support.ui.ExpectedConditions;
import org.openqa.selenium.support.ui.WebDriverWait;
import org.testng.Assert;
import org.testng.ITestResult;
import org.testng.annotations.AfterMethod;
import org.testng.annotations.BeforeMethod;
import org.testng.annotations.Test;

import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.StandardCopyOption;
import java.time.Duration;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;

public class LoginTest {
    private WebDriver driver;
    private WebDriverWait wait;

    @BeforeMethod
    public void setUp() {
        driver = new ChromeDriver();
        wait = new WebDriverWait(driver, Duration.ofSeconds(10));
        driver.manage().window().maximize();
    }

    @Test
    public void testInvalidLoginShowsError() {
        driver.get("https://example.com/login");

        WebElement usernameInput = wait.until(ExpectedConditions.visibilityOfElementLocated(By.id("username")));
        usernameInput.sendKeys("wronguser");

        WebElement passwordInput = driver.findElement(By.id("password"));
        passwordInput.sendKeys("wrongpass");

        WebElement loginButton = driver.findElement(By.id("loginBtn"));
        loginButton.click();

        WebElement errorMsg = wait.until(ExpectedConditions.visibilityOfElementLocated(By.id("error-message")));
        Assert.assertTrue(errorMsg.isDisplayed(), "Error message should be displayed on invalid login");
    }

    @AfterMethod
    public void tearDown(ITestResult result) {
        if (ITestResult.FAILURE == result.getStatus()) {
            takeScreenshot(result.getName());
        }
        if (driver != null) {
            driver.quit();
        }
    }

    private void takeScreenshot(String testName) {
        try {
            File srcFile = ((TakesScreenshot) driver).getScreenshotAs(OutputType.FILE);
            String timestamp = LocalDateTime.now().format(DateTimeFormatter.ofPattern("yyyyMMdd_HHmmss"));
            Path destPath = Path.of("screenshots", testName + "_" + timestamp + ".png");
            Files.createDirectories(destPath.getParent());
            Files.copy(srcFile.toPath(), destPath, StandardCopyOption.REPLACE_EXISTING);
            System.out.println("Screenshot saved to: " + destPath.toAbsolutePath());
        } catch (IOException e) {
            System.err.println("Failed to save screenshot: " + e.getMessage());
        }
    }
}

This test class uses Selenium WebDriver with TestNG to automate a login failure scenario.

setUp() initializes the Chrome browser and sets an explicit wait.

testInvalidLoginShowsError() opens the login page, enters wrong credentials, clicks login, and asserts the error message is visible.

tearDown() runs after each test. If the test failed, it calls takeScreenshot() to capture the browser screen and save it with a timestamped filename in the screenshots folder. Then it closes the browser.

takeScreenshot() uses Selenium's TakesScreenshot interface to get the screenshot file, creates the folder if needed, and saves the file with a name that includes the test method name and current time. This helps identify which test failed and when.

This approach ensures that any failure during the test run is documented visually, helping debugging.

Common Mistakes - 4 Pitfalls

Not using explicit waits before interacting with elements

Taking screenshot only inside the test method

Hardcoding screenshot file paths without creating directories

Using fixed screenshot file names

Bonus Challenge

Now add data-driven testing with 3 different invalid username and password combinations

Show Hint

Practice

1. What is the main purpose of taking a screenshot on test failure in Selenium Java?

easy

A. To automatically fix the test errors

B. To speed up the test execution

C. To visually capture the state of the application at failure

D. To reduce the size of the test report

Solution

1. Step 1: Understand the role of screenshots in testing

   Screenshots help testers see what the application looked like when a test failed.

2. Step 2: Identify the benefit of visual evidence

   This visual evidence helps diagnose issues faster and more clearly than logs alone.

3. Final Answer:

   To visually capture the state of the application at failure -> Option C

4. Quick Check:

   Screenshot = Visual failure evidence [OK]

Hint: Screenshots show what failed visually, not fix or speed tests [OK]

Common Mistakes:

• Thinking screenshots fix errors automatically
• Believing screenshots speed up tests
• Assuming screenshots reduce report size

2. Which Selenium interface is used to capture screenshots in Java?

easy

A. WebDriver

B. JavascriptExecutor

C. Alert

D. TakesScreenshot

Solution

1. Step 1: Recall Selenium interfaces for screenshots

   The TakesScreenshot interface provides the method to capture screenshots.

2. Step 2: Differentiate from other interfaces

   Other interfaces like WebDriver control browser, Alert handles popups, and JavascriptExecutor runs JS scripts.

3. Final Answer:

   TakesScreenshot -> Option D

4. Quick Check:

   TakesScreenshot = Capture screenshots [OK]

Hint: Use TakesScreenshot interface to capture images [OK]

Common Mistakes:

• Using WebDriver directly for screenshots
• Confusing Alert or JavascriptExecutor with screenshot capture
• Not casting driver to TakesScreenshot

3. What will happen if you run this code snippet after a test failure?

File srcFile = ((TakesScreenshot)driver).getScreenshotAs(OutputType.FILE);
FileUtils.copyFile(srcFile, new File("screenshots/fail.png"));

medium

A. Compilation error due to missing cast

B. Screenshot saved as fail.png in screenshots folder

C. Runtime error because FileUtils is undefined

D. Screenshot saved but file name is random

Solution

1. Step 1: Analyze the screenshot capture code

   The driver is cast to TakesScreenshot and screenshot saved as a file named "fail.png" in the "screenshots" folder.

2. Step 2: Check for errors or randomness

   FileUtils.copyFile copies the screenshot correctly; file name is fixed as "fail.png" so no randomness.

3. Final Answer:

   Screenshot saved as fail.png in screenshots folder -> Option B

4. Quick Check:

   Code saves fixed-name screenshot file [OK]

Hint: Casting driver and copyFile saves fixed screenshot file [OK]

Common Mistakes:

• Forgetting to cast driver to TakesScreenshot
• Not importing or defining FileUtils
• Expecting random file names without code for it

4. Identify the error in this code snippet for saving a screenshot on failure:

File srcFile = driver.getScreenshotAs(OutputType.FILE);
FileUtils.copyFile(srcFile, new File("screenshots/error.png"));

medium

A. driver must be cast to TakesScreenshot before calling getScreenshotAs

B. FileUtils.copyFile method does not exist

C. OutputType.FILE is invalid for screenshots

D. File path must be absolute, not relative

Solution

1. Step 1: Check method call on driver

   The getScreenshotAs method belongs to TakesScreenshot, so driver must be cast before calling it.

2. Step 2: Verify other parts

   FileUtils.copyFile exists and OutputType.FILE is correct. Relative paths are allowed if folder exists.

3. Final Answer:

   driver must be cast to TakesScreenshot before calling getScreenshotAs -> Option A

4. Quick Check:

   Cast driver to TakesScreenshot before screenshot [OK]

Hint: Always cast driver to TakesScreenshot before getScreenshotAs [OK]

Common Mistakes:

• Calling getScreenshotAs directly on WebDriver
• Assuming OutputType.FILE is wrong
• Thinking relative paths cause errors

5. You want to attach a screenshot to your test report only when a test fails. Which approach correctly implements this in Selenium Java with TestNG?

@AfterMethod
public void tearDown(ITestResult result) {
  if (result.getStatus() == ITestResult.FAILURE) {
    File src = ((TakesScreenshot)driver).getScreenshotAs(OutputType.FILE);
    File dest = new File("screenshots/" + result.getName() + ".png");
    FileUtils.copyFile(src, dest);
    // Attach dest to report here
  }
  driver.quit();
}

hard

A. This code saves screenshot only on failure and attaches it correctly

B. Screenshot is saved on every test, not just failures

C. FileUtils.copyFile will throw error without try-catch

D. result.getName() returns null, so file name is invalid

Solution

1. Step 1: Check condition for failure

   The code checks if test status is FAILURE before taking screenshot, so it runs only on failures.

2. Step 2: Verify screenshot saving and naming

   Screenshot saved with test method name, which is valid. Attaching to report is indicated as a comment.

3. Step 3: Confirm no errors in logic

   FileUtils.copyFile may throw IOException but typically handled or declared; this snippet focuses on logic correctness.

4. Final Answer:

   This code saves screenshot only on failure and attaches it correctly -> Option A

5. Quick Check:

   Screenshot on failure only with correct naming [OK]

Hint: Use ITestResult.FAILURE check to save screenshots only on failure [OK]

Common Mistakes:

• Taking screenshots regardless of test result
• Not handling exceptions from file operations
• Assuming getName() returns null