python - Why does Selenium's wait.until_not(EC.invisibility_of_element_located) wait for too long for a loader to disappear?

Question

Which selenium.webdriver.support.expected_conditions are better to use when waiting for the invisibility of an element? In my case, I input data into a form, click save and wait for a loader to disappear

from selenium.webdriver.support import expected_conditions as EC 
wait = WebDriverWait(driver, 10)
wait.until(EC.presence_of_element_located((SelectBy.CSS_SELECTOR, ".spinner")))
debug("loader appeared")
wait.until(EC.invisibility_of_element_located((SelectBy.CSS_SELECTOR, ".spinner")))
debug("loader disappeared")

In the output, I see that the second wait is executed for 20 seconds (my global implicit wait is 20 seconds)

360ms ?     [debug] loader appeared
21s 141ms ? [debug] loader disappeared

The locator is good, I am trying to understand what is wrong with the wait. Did anyone have similar problems? I would be happy for any suggestions.

Answer 1

Your wait operations are stacking on each other because your code is chained.

Let me explain with your code:

# 1. create a wait object
wait = WebDriverWait(driver, 10)

# 2. execute a wait statement
wait.until(EC.presence_of_element_located((SelectBy.CSS_SELECTOR, ".spinner")))
debug("loader appeared")

# 3. execute a wait statement
wait.until(EC.invisibility_of_element_located((SelectBy.CSS_SELECTOR, ".spinner")))
debug("loader disappeared")

Both wait statements (#2 and #3) are using the same wait object, so their execution will "stack":

1. Wait object will wait 10 seconds for a condition
2. Wait 10 seconds (inherited) + spinner appear
3. Wait 10 seconds (inherited) + spinner appear (inherited) + spinner disappear

Action #2 waits 10s. Action #3 waits 20s.