Quicker way to assert that an element does not exist

Question

The goal of my test is to assert that a popup does not appear after certain actions. Previously to test if the popup exist, i have used exception handling.

try:

    self.driver.find_element_by_id("fancybox-close").click()

except Exception ('ElementNotVisibleException'):

    print "No popup"

This works fine for the test : to assert if popup exists.

But as soon as i change the goal to : assert if popup does not exist

the exception handling solution becomes very expensive (exception handling takes a lot of time in python) and a test that would execute in 3 secs now takes up to a minute.

Is there a way around this? A quicker way to check if an element does not exist using webdriver python binding ?

Answer 1

I haven't used the Python bindings, but as far as I know they should be equivalent to the Java ones.

If I were you I would try to find the Python equivalents of findElements() and isDisplayed() that are available in the Java bindings.

For example, I would do something similar to this:

// ...
myElementList = driver.findElements(By.Id("fancybox-close"))
if (myElementList.isEmpty()) {
    // The element doesn't exist. findElements, in plural, returns a list of the matching elements, or an empty list if no one is found
else {
    // We know it exists, now we need to know if it's displayed (visible) or not
    if (myElementList[0].isDisplayed()) {
        // This means the element is visible
    else {
        // ...
    }

}

Hope it helps

Answer 2

The test is slow not due to slow exception handling, but because driver waits for elements thats are not found. In this case driver waits for the pop-up - maybe it will appear.

Try to use self.driver.implicitly_wait(0)

This will tell driver not to wait if it cannot find some elements.

Answer 3

Here's another example much like the one from Ignacio, but in C#:

    //Displayed
    public static bool IsElementDisplayed(this IWebDriver driver, By element)
    {
        if (driver.FindElements(element).Count > 0)
        {
            if (driver.FindElement(element).Displayed)
                return true;
            else
                return false;
        }
        else
        {
            return false;
        }
    }

    //Enabled
    public static bool IsElementEnabled(this IWebDriver driver, By element)
    {
        if (driver.FindElements(element).Count > 0)
        {
            if (driver.FindElement(element).Enabled)
                return true;
            else
                return false;
        }
        else
        {
            return false;
        }
    }

Answer 4

You can potentially speed it up using various ways:

• Implicit wait This is mentioned by tstempko. However, implicit wait has a drawback. This makes the driver to not waiting for all UI element when it is set to '0'. In your case, it is not ideal. There might a time that you really have to wait for UI element to show up, then your test will break for no valid reason.
• Explicit wait You can setup an explicit wait just for this call. This allows a more robust way of waiting for the UI element to show up.

• Javascript executor for me, there are some web elements which are just too 'unreliable' to detect all the time. What I will use is the javascript executor like this:

  String cmd = "$('#header-username').click()";
  ((JavascriptExecutor)driver).executeScript(cmd);
  

  Good thing about JavaScriptExcutor is that as long as the javascript is loaded, you can execute it. The browser does not need to wait for the element to be rendered. The downside of this is that it is not mimic user's behavior. I use this only to get through to the next test area that I am interested in.

On a side note, rather than the try-except method you have, you might want to try to code it this way:

wait = new WebDriverWait(driver, TIMEOUT);
e = wait.until(ExpectedConditions.visibilityOf(oldPasswordField))
e.click()

Unfortunately, my code is in Java. I think there is a similar method in Python equivalent.

Answer 5

In python, to assert that something is visible use:

element.is_displayed()

is_displayed() will wait until the element is visible or it will timeout

If you want to assert that an element is not visible use:

element.is_not_displayed()

if the element is not displayed it will return True immediately

Answer 6

A safe way I have used over the last few months has been extracting the closest element node and verifying it as an XML

WebElement element = driver.findElement(By.css("some path to a div"));
String documentNode = ((JavascriptExecutor) driver).executeScript("return arguments[0].outerHTML;", element);

That will return the Text. (Here is a sample of what you will get as output.)

"<div><div>some test</div></div> \n \n \n"

Trim it, then I have converted it to a document and safely xpath or parse the nodes manually. That's it. This has been way faster and no chance of stale state. No more waiting indefinitely.

Hope this helps.