Selenium Java - Handling Windows, Frames, and Alerts
In a test, you need to enter a dynamic value into a prompt alert and then verify the page updates accordingly. Which code snippet correctly uses a variable for input and verifies the result?
```java
String userInput = "Tester";
Alert prompt = driver.switchTo().alert();
prompt.sendKeys(userInput);
prompt.accept();
String message = driver.findElement(By.id("msg")).getText();
assertTrue(message.contains(userInput));
```
