public void testUserCanLogInAndLogOutAgain() {
    WebDriver driver = new HtmlUnitDriver();
    driver.get("http://localhost:8080/yourapp");
    WebElement login = driver.findElement(By.id("login.link"));
    login.click();

    WebElement usernameField = driver.findElement(By.id("login.username"));
    usernameField.sendKeys("username");

    WebElement passwdField = driver.findElement(By.id("login.password"));
    passwdField.sendKeys("password");

    WebElement loginButton = driver.findElement(By.id("login.submit"));
    loginButton.submit();

    // ensure that the user's log in was successful
    // throws a NoSuchElementException if the text isn't found
    driver.findElement(By.xpath("//p[contains(text(), 'Welcome, username!')]"));

    WebElement logout = driver.findElement(By.id("logout.link"));
    logout.click();

    // ensure that the user's log out was successful
    driver.findElement(By.xpath("//p[contains(text(), 'Please log in')]"));
}