How to create your own WebDriverWait conditions

In our previous post, we have discussed how to use explicit wait in selenium with python, python library provides many different conditions to wait for an element.

Still if one likes to customise & create their own webdriverwait conditions, you can!

Let’s first understand the logic behind webdriverwait implementation

If you go to the implementation of below line –

WebDriverWait(driver, 10).until(EC.presence_of_element_located((By.XPATH, "someXPATH")))

# expected_conditions.py # from selenium


class presence_of_element_located(object):
    """ An expectation for checking that an element is present on the DOM
    of a page. This does not necessarily mean that the element is visible.
    locator - used to find the element
    returns the WebElement once it is located
    """
    def __init__(self, locator):
        self.locator = locator

    def __call__(self, driver):
        return _find_element(driver, self.locator)

From the above code, we can get to know

__call__ method will continue polling and verifying the condition till it returns false, comes out of wait once the condition is true

Polling happens in each 0.5 seconds

If the condition is never false, then it won’t continue polling rather will throw TimeOutException once the wait time passes. [mentioned as in the WebDriverWait(driver, someTime)]

So we will create our own webdriverwait condition by using above logic –

We will use this demo portal – https://qavbox.github.io/demo/delay/

If you click on the Click me button, there will be paragraph text displayed after 5 sec.

We have to wait till the text appears on browser screen and then get the text.

class wait_till_text_appears(object):

    def __init__(self, locator, text_):
        self.locator = locator
        self.text = text_

    def __call__(self, driver):
        try:
            element_text = driver.find_element(*self.locator).text
            # print("Polllllllll" + element_text)
            return self.text in element_text
        except BaseException:
            return False

This above will accept 2 parameters, locator for which we need to get the text and the text string

__call__ method will verify if the locator text matched to the text string,

return self.text in element_text – if the text not yet appeared, then this method will return false and will poll or wait till it returns true i.e – wait till the text matches

How to use this above customised wait method?

WebDriverWait(driver, 10).until(wait_till_text_appears((By.XPATH, "//p[@id='two']"), "here!"))

Complete code –

def test_Sample1():
    driver = webdriver.Chrome("/Users/skpatro/sel/chromedriver")
    driver.get("https://qavbox.github.io/demo/delay/")
    driver.find_element_by_css_selector("[value=''Click me!]").click()
    print("Before waiting - " + driver.find_element_by_id("two").text)
    WebDriverWait(driver, 10).until(wait_till_text_appears((By.XPATH, "//p[@id='two']"), "here!")) 
    # above line will wait till the text apears
    print("After waiting - " + driver.find_element_by_id("two").text)

Hope this helps!