It’s a problem I’ve encountered many times: building out a test and getting to an element I need to click on or test its attributes or text only to find out that it’s being dynamically loaded by Javascript. When this happens I always get the same error in the console.

ElementNotVisibleException: Message: element not visible

It’s frustrating since virtually all help threads Ive found on Stack Overflow and on other blogs are close but never offered help that actually works. Maybe because my issue is not quite the same or because I write my tests differently, but truly I’ve never gotten any of those solutions to work. The following is a list of things that are either really bad ideas or just never worked for me:

• Sleep the browser
• Programmatically move the cursor 1px in order to find a button hit state
• Injecting click actions into the browser developer console (ewww)
• Use XPATH instead of CSS Locator
• Get the size of the element first then click
• etc

Finally just breaking down and looking at the Docs for Waits in Selenium/Python there, of course seems to be some promise. The example they give is as follows:

from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC

driver = webdriver.Firefox()
driver.get("http://somedomain/url_that_delays_loading")
try:
    element = WebDriverWait(driver, 10).until(
        EC.presence_of_element_located((By.ID, "myDynamicElement"))
    )
finally:
    driver.quit()

Scanning the code quickly, I figured this was right up my alley. I copied the code, changed the placeholder element to the one I’m looking for, saved the file, rebuilt Docker, and ran the test. Same failure. Literally this code changed nothing. It didn’t wait, the element was still not visible and the test still failed. Ugg.

I read back through the code more thoroughly and noticed the Expected Condition line of

presence_of_element_located

which caught my eye. Presence. Ahh, right ok. My issue was not that the element was not present, which can also happen. My issue this time as you recall above was that the element was not Visible. Ok, dig deeper into the docs and look at the full list of Expected Conditions which are:

title_is
title_contains
presence_of_element_located
visibility_of_element_located
visibility_of
presence_of_all_elements_located
text_to_be_present_in_element
text_to_be_present_in_element_value
frame_to_be_available_and_switch_to_it
invisibility_of_element_located
element_to_be_clickable - it is Displayed and Enabled.
staleness_of
element_to_be_selected
element_located_to_be_selected
element_selection_state_to_be
element_located_selection_state_to_be
alert_is_present

Ahh, look at this. Visibility conditions. This is looking promising! Let’s make a quick change to something like:

from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC

driver = webdriver.Firefox()
driver.get("http://somedomain/url_that_delays_loading")
try:
    element = WebDriverWait(driver, 10).until(
        EC.visibility_of_element_located((By.ID, "myDynamicElement"))
    )
finally:
    driver.quit()

Save the file, rebuild Docker, run the test. While testing in our dev environment I have Docker run the test with a headed browser, usually Chrome or FF so I’m able to watch it run. This time around something is different. The test properly pauses while the page content is loading in dynamically then once loaded the test proceeded. Success! That was it.