Is using the method driver.close() required?

Question

Let's say

1. I have a window 1. I have performed an event on the window 1 that makes window 2 to appear.

2. Now I switched to the window 2 and clicked a button on it which closes window 2.

If I use driver.close() after I performed an event which caused the window to close, sometimes it throws NoSuchWindowException.

If I don't use the driver.close() then sometimes driver.getWindowHandles().size() returns 2 even when there is only one window and I have waited enough time to number of windows become 1.

I refresh driver.getWindowHandles() and check for the driver.getWindowHandles().size() to become 1 but it doesn't sometimes.

My question is, do I need to use the method driver.close() after I clicked the button that caused the window to close? How to use the driver.close() correctly.

EDIT: Yes, it is a problem. If selenium doesn't realize window2 has been closed, it keeps returning the handles to be 2. Suppose that I closed window2 and switched back to window1 and performed an event which opens window3. Now I want to switch to window3. Here is the problem because Selenium still think windows2 exists and now there are three windows according to the Selenium.

String window1Handle = driver.getWindowHandle();
//Now I have oepend window3
//According to the Selenium there are 3 windows
// So driver.getWindowHandles().size() returns 3
 for (String window : driver.getWindowHandles() {
        if (!window.equals(window1Handle)) {
                  driver.switchTo().window();

The above line may throw exception because driver is trying to switch to a window which has already been closed"

Answer 1

No you don't need to perform a driver.close(), if anything is left open, when you perform a driver.quit() at the end of your test WebDriver will clean up and make sure that everything is shut down correctly.

Selenium can track how many windows are open, if you are seeing window handles for windows that are closed that sounds like a potential bug. Bear in mind that it may take some time for Selenium to realise that the window has been closed, you could try using an explicit wait to wait for the count of window handles to drop back down to 1, you'll need to add the following ExpectedCondition:

  public static ExpectedCondition<Boolean> numberOfWindowsToBe(final int numberOfWindows) {
    return new ExpectedCondition<Boolean>() {
      @Override
      public Boolean apply(WebDriver driver) {
        return driver.getWindowHandles().size() == numberOfWindows;
      }
    };
  }

Then you can use it by doing:

    WebDriverWait wait = new WebDriverWait(driver, 15, 100);
    wait.until(numberOfWindowsToBe(1));

or you could just try closing the window by performing a driver.close() and catching the NoSuchWindowException e.g.

try{
    driver.close();
} catch(NoSuchWindowException ignored){
    System.out.println("Window already closed");
}

This should give Selenium the kick it needs to realise that the window has been closed (Although to be honest I wouldn't bother).

*EDIT*

So it sounds like the problem is that you have multiple window handles and you don't know which one is the window that has been closed, and which one is your newly opened window. One workaround would be to track the window handles in a Map. Every time you open a new window store the window handle in the map like this:

Map<String, String> openedWindows = new HashMap<String, String>();
openedWindows.put("Window 1", driver.getWindowHandle());

You will then know which window handle is associated with your window, you can then remove windows from the map as they are closed. You will know which handles that are still being reported are actually closed and which are being reported in error.

Really this sounds like a bug in Selenium window handling and I would suggest you raise an issue on the issue tracker with a minimal test script that reproduces the problem. Of course the other option above is still valid, try and close the window but catch the exception and see if that gives Selenium the kick it needs to remove it from the list of window handles.