为什么 Selenium python package 中没有 expected_conditions all_of、none_of 和 any_of？

Question

I am using Selenium with Python and came across the need to use WebDriverWait and selenium.webdriver.support.expected_conditions in it. I have to wait for an element to be removed and for another to be displayed, so I was wishing to use all_of and none_of to make the conditions easier to understand:

WebDriverWait(browser, 10).until(
    EC.all_of(
        EC.presence_of_element_located((By.CSS_SELECTOR, "span[title='VMC OIC-2 batch 2022'")),
        EC.none_of(
            EC.presence_of_element_located((By.CSS_SELECTOR, "div#startup")),
            EC.presence_of_element_located((By.CSS_SELECTOR, "div#initial-startup"))
        )
    )
)

Unforunately, I received this error:

AttributeError: module 'selenium.webdriver.support.expected_conditions' has no attribute 'all_of'

On further inspection through raw printing I got to know that none of the any_of, all_of and none_of conditions were working.

Another thing to note is that the mentioned conditions are present in Selenium with Java. I could find an issue talking about this, and it seems like any_of, all_of and none_of were eventually added to expected_conditions as is evident in the Selenium repository's corresponding file: expected_conditions.py (the last three functions).

This question is demanding an explanation, not an alternative, I am well aware I can write a function to do the same task or even copy the function listed in expected_conditions.py but I would really like to know why these functions are present in the repository and absent in the working package.

Thanks for reading!

Answer 1

pip install selenium==4.0.0.a7

install selenium 4 alpha version, there will be no new updates in selenium 3.141

https://github.com/SeleniumHQ/selenium/releases

you can see last update for v3 was on Dec 2018. click see new tags to see latest v4 releases

the documentation is updated as per selenium 4

https://github.com/SeleniumHQ/seleniumhq.github.io/issues/627

Answer 2

They have been introduced in this commit . While the version in PyPi repository is 3.141 that commit will likely be delivered in 4.0.0 version.

Answer 3

expected_conditions.all_of(*expected_conditions)

selenium.webdriver.support.expected_conditions.all_of(*expected_conditions) is the expectation that all of multiple expected conditions is true. Equivalent to a logical AND . It is defined as:

def all_of(*expected_conditions):
    """ An expectation that all of multiple expected conditions is true.
    Equivalent to a logical 'AND'.
    Returns: When any ExpectedCondition is not met: False.
    When all ExpectedConditions are met: A List with each ExpectedCondition's return value. """
    def all_of_condition(driver):
    results = []
    for expected_condition in expected_conditions:
        try:
        result = expected_condition(driver)
        if not result:
            return False
        results.append(result)
        except WebDriverException:
        return False
    return results
    return all_of_condition
    

An example

WebDriverWait(browser, 10).until(EC.all_of(
    EC.presence_of_element_located((By.CSS_SELECTOR, "span[title='VMC OIC-2 batch 2022']")),
    EC.presence_of_element_located((By.CSS_SELECTOR, "div#startup")),
    EC.presence_of_element_located((By.CSS_SELECTOR, "div#initial-startup"))
))

---

expected_conditions.any_of(*expected_conditions)

selenium.webdriver.support.expected_conditions.any_of(*expected_conditions) is the expectation that all of multiple expected conditions is true. Equivalent to a logical AND . It is defined as:

def any_of(*expected_conditions):
    """ An expectation that any of multiple expected conditions is true.
    Equivalent to a logical 'OR'.
    Returns results of the first matching condition, or False if none do. """
    def any_of_condition(driver):
    for expected_condition in expected_conditions:
        try:
        result = expected_condition(driver)
        if result:
            return result
        except WebDriverException:
        pass
    return False
    return any_of_condition

An example

WebDriverWait(browser, 10).until(EC.any_of(
    EC.presence_of_element_located((By.CSS_SELECTOR, "span[title='VMC OIC-2 batch 2022']")),
    EC.presence_of_element_located((By.CSS_SELECTOR, "div#startup")),
    EC.presence_of_element_located((By.CSS_SELECTOR, "div#initial-startup"))
))

---

expected_conditions.none_of(*expected_conditions)

selenium.webdriver.support.expected_conditions.none_of(*expected_conditions) is the expectation that all of multiple expected conditions is true. Equivalent to a logical AND . It is defined as:

def none_of(*expected_conditions):
    """ An expectation that none of 1 or multiple expected conditions is true.
    Equivalent to a logical 'NOT-OR'.
    Returns a Boolean """
    def none_of_condition(driver):
    for expected_condition in expected_conditions:
        try:
        result = expected_condition(driver)
        if result:
            return False
        except WebDriverException:
        pass
    return True
    return none_of_condition

An example

WebDriverWait(browser, 10).until(EC.none of(
    EC.presence_of_element_located((By.CSS_SELECTOR, "span[title='VMC OIC-2 batch 2022']")),
    EC.presence_of_element_located((By.CSS_SELECTOR, "div#startup")),
    EC.presence_of_element_located((By.CSS_SELECTOR, "div#initial-startup"))
))

---

Note

You have to add the following imports:

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

---

This usecase

As per the CHANGELOGS there was a fix to the all_of() function in Selenium 4.0 Alpha 3 :

• Fixing check of type of a returned element in a test for all_of condition

---

Solution

Upgrade the Selenium python client version to recent Selenium 4.0 Beta 1