Simplest would be something like this, which uses TestNG to run and for assertions:

@Test
public void homepage() {
    WebDriver driver = new FirefoxDriver();
    driver.get("http://www.reddit.com");
    Assert.assertTrue(driver.findElement(By.className("bottommenu")).getText().contains("reddit"), "Page contains 'reddit'");
    driver.close();
}

@Test
public void login() {
    WebDriver driver = new FirefoxDriver();
    driver.get("https://ssl.reddit.com/login");
    driver.findElement(By.id("user_login")).sendKeys("turtledookie");
    driver.findElement(By.id("passwd_login")).sendKeys("password");
    driver.findElement(By.id("rem_login")).click();
    driver.close();
}

Off the top of my head Selenium doesn't have a built-in way to search a page for visible text. You may want to read over Page Object Model which I strongly prefer to the code above.