Create custom wait until condition in Python

Question

I tried to create a function with custom wait condition in Python. However, I get an error:

TypeError: 'bool' object is not callable

def waittest(driver, locator, attr, value):
    element = driver.find_element_by_xpath(locator)
    if element.get_attribute(attr) == value:
        return element
    else:
        return False
wait = WebDriverWait(driver, 10)
element = wait.until(waittest(driver, '//div[@id="text"]', "myCSSClass", "false"))    

Answer 1

WebDriverWait(driver, 10).until() accepts a callable object which will accept an instance of a webdriver (driver is our example) as an argument. The simplest custom wait, which expects to see 2 elements, will look like

WebDriverWait(driver, 10).until(
    lambda wd: len(wd.find_elements(By.XPATH, 'an xpath')) == 2
)

The waittest function has to be rewritten as:

class waittest:
    def __init__(self, locator, attr, value):
        self._locator = locator
        self._attribute = attr
        self._attribute_value = value

    def __call__(self, driver):
        element = driver.find_element_by_xpath(self._locator)
        if element.get_attribute(self._attribute) == self._attribute_value:
            return element
        else:
            return False

And then it can be used as

element = WebDriverWait(driver, 10).until(
    waittest('//div[@id="text"]', "myCSSClass", "false")
)

Answer 2

what I really end up to do is using lambda

self.wait.until(lambda x: waittest(driver, "//div[@id="text"]", "myCSSClass", "false"))