Question

当我尝试测试包含表格的网页时，我一直在设置StaleElementReferenceException。该表有点[以及其他一些信息]和两个单独的阻塞点的状态，每个阻塞点都有一个“是”和“否”的切换状态按钮。

在此特定代码中，过程为：

单击复选框以仅显示阻止点。
如果表格中没有阻止点，则表示您已完成。否则...
保存第一行中点的名称＆amp;检查第一个阻止状态。如果设置为“是”，请将其更改为“否”。
检查点是否仍然存在。如果是，请将第二个阻止状态更改为“否”，并确认该点已被删除。

我在代码中添加了注释，以帮助我遵循我的流程：

    # << Setup >>
    driver.get(url("/PointsTable/"))
    assertExpectedConditionTrue(driver, "By.XPATH", "//td")

    # < Confirm that the points blocking checkbox is enabled >
    if not driver.find_element_by_id("BlockedPoints").is_selected():
        assertExpectedConditionTrue(driver, "By.ID", "BlockedPoints")
        driver.find_element_by_id("BlockedPoints").click()
        assertCheckBoxEnabled(driver, "BlockedPoints")

    # < First check if any points have a blocking state >
    try:
        assertExpectedConditionTrue(driver, "By.XPATH", "//td[contains(text(), 'No data available in table')]", None, 3)
    except (NoSuchElementException):
        # < Until all the points are out of blocking state, begin changing blocking statuses
        #   to all the points >
        while True:
            # < Check if all the points are set to have no blocking statuses set to Yes >
            try:
                assertExpectedConditionFalse(driver, "By.XPATH", "//td[contains(text(), 'No data available in table')]", None, 2)
            except (NoSuchElementException, TimeoutException):
                break

            # < Save the name of the point
            # Check the first blocking status.  If it is blocking, set the block to No >
            assertExpectedConditionTrue(driver, "By.XPATH", "//td")
            myPointVal = driver.find_element_by_xpath("//td").text

            try:
                assertExpectedConditionTrue(driver, "By.XPATH", "//tbody/tr[1]/td[5]/div/button[@class='btn active btn-success btn-small point-button']", None, 2)
            except (NoSuchElementException):
                assertExpectedConditionTrue(driver, "By.XPATH", "//tbody/tr[1]/td[5]/div/button[@class='btn btn-small point-button']")
                driver.find_element_by_xpath("//tbody/tr[1]/td[5]/div/button[@class='btn btn-small point-button']").click()

            # < Save the name of the point again.  Compare it to the original saved point
            #    If the name is the same, then the second blocking status needs to be set to No
            #    If the name is different, that means the point in question is no longer blocked >
            assertExpectedConditionTrue(driver, "By.XPATH", "//td")
            if myPointVal == driver.find_element_by_xpath("//td").text:
                assertExpectedConditionTrue(driver, "By.XPATH", "//tbody/tr[1]/td[6]/div/button[@class='btn btn-small point-button']")
                driver.find_element_by_xpath("//tbody/tr[1]/td[6]/div/button[@class='btn btn-small point-button']").click()
                assertExpectedConditionFalse(driver, "By.XPATH", "//td", myPointVal)

当一个点已经删除了所有阻塞状态时，它实际上会从表中消失，这是我异常的原因。代码并不总是在同一行上失败，但是当它失败时，它总是在我尝试点击“是”或“否”按钮的行上，这很可能是因为在一个点之后表格发生变化已成功从表中删除。

i.e. driver.find_element_by_xpath("//tbody/tr[1]/td[6]/div/button[@class='btn btn-small point-button']").click()

它有时会超过代码的这一部分。在我试图点击某个按钮的不同部分失败了。（1）刷新页面，或者（2）导航到第2页，其中XPATH地址是相同的，但是对象在XPATH地址已更改。由于here列出的原因，我确实理解我遇到此问题的原因。我的问题似乎与“元素不再附加到DOM”一致。

到目前为止，我已尝试在可能导致更改表的位置使用time.sleep（）和driver.implicitly_wait（），但问题仍然存在。我该如何解决这个问题？

Answer 1

使用 inplicitly_wait（），如果时间设置得足够高，将解决StaleElementReferenceException问题。但是，隐式等待也导致测试用例需要很长时间才能运行。我使用我发现here，here和here的提示解决了这个问题。

出现此问题是因为在对表进行更改时，不再将正在引用的元素附加到DOM。因此，我专门为处理可能过时的元素创建了定义。

def waitForNonStaleElement(driver, type, element):
    strategy = {
            "id":           driver.find_element_by_id,
            "link_text":    driver.find_element_by_link_text,
            "name":         driver.find_element_by_name,
            "xpath":        driver.find_element_by_xpath
            }
    lhsType, rhsType = type.split(".", 1)
    find_element = strategy.get(rhsType.lower())

    try:
        find_element(element)
    except StaleElementReferenceException:
        waitForNonStaleElement(driver, type, element)
    except TypeError:
        raise TypeError("ERROR : CODE TO HANDLE \""+element+"\" TYPE NEEDS TO BE CREATED")


def waitForNonStaleElementClick(driver, type, element):
    strategy = {
            "id":           driver.find_element_by_id,
            "link_text":    driver.find_element_by_link_text,
            "name":         driver.find_element_by_name,
            "xpath":        driver.find_element_by_xpath
            }
    lhsType, rhsType = type.split(".", 1)
    find_element = strategy.get(rhsType.lower())

    try:
        waitForNonStaleElement(driver, type, element)
        find_element(element).click()
    except StaleElementReferenceException:
        waitForNonStaleElementClick(driver, type, element)
    except TypeError:
        raise TypeError("ERROR : CODE TO HANDLE \""+element+"\" TYPE NEEDS TO BE CREATED")


def waitForNonStaleElementText(driver, type, element):
    strategy = {
            "id":           driver.find_element_by_id,
            "link_text":    driver.find_element_by_link_text,
            "name":         driver.find_element_by_name,
            "xpath":        driver.find_element_by_xpath
            }
    lhsType, rhsType = type.split(".", 1)
    find_element = strategy.get(rhsType.lower())

    try:
        return find_element(element).text
    except StaleElementReferenceException:
        waitForNonStaleElementText(driver, type, element)
    except TypeError:
        raise TypeError("ERROR : CODE TO HANDLE \""+element+"\" TYPE NEEDS TO BE CREATED")

waitForNonStaleElement（）用于确认元素不再陈旧。 waitForNonStaleElementClick（）允许我点击可能过时的元素。 waitForNonStaleElementText（）允许我从可能过时的元素中检索文本。

然后我使用这些方法重写了搜索代码：

# << Setup >>
driver.get(url("/PointsBlocking/"))
assertExpectedConditionTrue(driver, "By.XPATH", "//td")

if not driver.find_element_by_id("BlockedOnlyCheckbox").is_selected():
    assertExpectedConditionTrue(driver, "By.ID", "BlockedOnlyCheckbox")
    driver.find_element_by_id("BlockedOnlyCheckbox").click()
    assertCheckBoxEnabled(driver, "BlockedOnlyCheckbox")

waitForNonStaleElement(driver, "By.XPATH", "//td")

try:
    assertExpectedConditionTrue(driver, "By.XPATH", "//td", "No data available in table", 1)
except (TimeoutException):
    while True:
        try:
            assertExpectedConditionFalse(driver, "By.XPATH", "//td", "No data available in table", 1)
        except (TimeoutException):
            break

        assertExpectedConditionTrue(driver, "By.XPATH", "//td")
        pointName = waitForNonStaleElementText(driver, "By.XPATH", "//td")

        try:
            assertExpectedConditionTrue(driver, "By.XPATH", "//tbody/tr[1]/td[5]/div/button[@class='btn active btn-success btn-small point-button']", None, 1)
        except NoSuchElementException:
            assertExpectedConditionTrue(driver, "By.XPATH", "//tbody/tr[1]/td[5]/div/button[@class='btn btn-small point-button']")
            waitForNonStaleElementClick(driver, "By.XPATH", "//tbody/tr[1]/td[5]/div/button[@class='btn btn-small point-button']")

        tmp = waitForNonStaleElementText(driver, "By.XPATH", "//td")

        if pointName == tmp:
            assertExpectedConditionTrue(driver, "By.XPATH", "//tbody/tr[1]/td[6]/div/button[@class='btn btn-small point-button']")
            waitForNonStaleElementClick(driver, "By.XPATH", "//tbody/tr[1]/td[6]/div/button[@class='btn btn-small point-button']")
            waitForNonStaleElementClick(driver, "By.XPATH", "//td")

希望如果遇到与我相同的问题，这将有助于某人。

Answer 2

如果您的问题是您点击了一个尚不存在的元素，并且您想验证元素是否存在，您可以执行下一步：

使用搜索元素列表的方法查找元素（返回列表）
检查列表中是否有任何元素（count> 0）
如果count为0，则表示没有找到任何元素，因此它不存在

你也可以尝试使用try-catch，但它更复杂。

单击更改的表的按钮时发生StaleElementReferenceException（Python＆gt; Selenium Webdriver）

2 个答案: