Selenium - visibility_of_element_located:__ init __()只需2个参数(给定3个)

Question

我在使用Selenium Python Bindings的测试代码中收到此错误:

>           twitter_campaigns = wait.until(EC.visibility_of_element_located(By.CSS_SELECTOR, TWITTER_CAMPAIGNS))
E           TypeError: __init__() takes exactly 2 arguments (3 given)

这就是我执行的:

class TestTwitter(TestLogin, TestBuying):

    def setup(self, timeout=10):
        self.driver = webdriver.Firefox()
        self.driver.get(BASEURL)
        self.driver.implicitly_wait(timeout)

    def test_campaigns_loaded(self, timeout=10):
        self.signin_action()
        self.view_twitter_dashboard()
        self.select_brand()
        wait = WebDriverWait(self.driver, timeout)
        twitter_campaigns = wait.until(EC.visibility_of_element_located(By.CSS_SELECTOR, TWITTER_CAMPAIGNS))
        assert True == twitter_campaigns

    def teardown(self):
        self.driver.close()

所以我想知道为什么我得到了上述错误,在我没有定义__init__()方法的所有类中,我将setUp和tearDown方法定义为pytest跟随.任何想法为什么要采取3 args？

Answer 1

你应该问的问题不是 "为什么它采取3 args",而是" 什么是3 args".您的回溯是指代码中非常特定的行,它存在问题所在.

根据这里的Selenium Python文档,selenium.webdriver.support.expected_conditions.visibility_of_element_located应该用元组调用; 它不是一个函数,而是一个实际上是一个类,它的初始化程序只需要一个超出隐式self的参数:

class visibility_of_element_located(object):
   # ...
   def __init__(self, locator):
       # ...

因此,您需要self使用两个嵌套括号调用:

wait.until(EC.visibility_of_element_located( ( By.CSS_SELECTOR, TWITTER_CAMPAIGNS ) ))

这意味着,而不是3个参数visibility_of_element_located,self并且By.CSS_SELECTOR,在TWITTER_CAMPAIGNS将与刚预计2个参数调用:隐式visibility_of_element_located.__init__和定位:一个self元组.