Temporarily bypassing implicit waits with WebDriver

问题

When using implicit waits, as advised here, I still sometimes want to assert the immediate invisibility or non-existence of elements.

In other words, I know some elements should be hidden, and want my tests make that assertion fast, without spending several seconds because of the (otherwise useful) implicit wait.

One thing I tried was a helper method like this:

// NB: doesn't seem to do what I want
private boolean isElementHiddenNow(String id) {
    WebDriverWait zeroWait = new WebDriverWait(driver, 0);
    ExpectedCondition<Boolean> c = invisibilityOfElementLocated(By.id(id));
    try {
        zeroWait.until(c);
        return true;
    } catch (TimeoutException e) {
        return false;
    }
}

But in the above code, the call to until() only returns after the implicit wait time has passed, i.e., it doesn't do what I wanted.

This is the only way I've found so far that works:

@Test
public void checkThatSomethingIsNotVisible()  {
    turnOffImplicitWaits();
    // ... the actual test
    turnOnImplicitWaits();
}

... where e.g. turnOffImplicitWaits() is a helper in common Selenium superclass:

protected void turnOffImplicitWaits() {
    driver.manage().timeouts().implicitlyWait(0, TimeUnit.SECONDS);
}

But that is not very elegant, I think. Is there any cleaner way to bypass the implicit wait occasionally?

回答1:

Given that Selenium doesn't seem to offer what I want directly (based on what Mike Kwan and Slanec said), this simple helper method is what I went with for now:

protected boolean isElementHiddenNow(String id) {
    turnOffImplicitWaits();
    boolean result = ExpectedConditions.invisibilityOfElementLocated(By.id(id)).apply(driver);
    turnOnImplicitWaits();
    return result;
}

private void turnOffImplicitWaits() {
    driver.manage().timeouts().implicitlyWait(0, TimeUnit.SECONDS);
}

private void turnOnImplicitWaits() {
    driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);
}

If the element is hidden or not present at all, the method returns true; if it is visible, returns false. Either way, the check is done instantly.

Using the above is at least much cleaner than littering the test cases themselves with calls to turnOffImplicitWaits() and turnOnImplicitWaits().

See also these answers for fined-tuned versions of the same approach:

• Using try-finally to turn implicit waits back on
• Using By locator as the parameter

回答2:

I would also suggest changing the parameter to a "By" locator for more flexibility when looking for the element.

protected boolean isElementHiddenNow(By locator) {
    turnOffImplicitWaits();
    boolean result = false;
    try {
       result = ExpectedConditions.invisibilityOfElementLocated(locator).apply(driver);
    }
    finally {
       turnOnImplicitWaits();
    }
    return result;
}

That way, you could search by css if needed rather than just id:

By PartLinkLocator = By.cssSelector("div.search-result div.row a");

'Course, your locator should probably be designed to return only one element (unlike the "By" example I quickly grabbed, which returns all part links in a css table of rows...) So, an "id" example would look like

By usernameLocator = By.id("inputEmail");
myResult = isElementHiddenNow(usernameLocator);

回答3:

My implementation:

using (driver.NoImplicitWait())
{
    ....
}

With extension method:

public static NoImplicitWait NoImplicitWait(this IWebDriver driver)
{
    return new NoImplicitWait(driver);
}

And class:

public sealed class NoImplicitWait : IDisposable
{
    private readonly IWebDriver _driver;

    public NoImplicitWait(IWebDriver driver)
    {
        _driver = driver;
        _driver.Manage().Timeouts().ImplicitlyWait(TimeSpan.FromSeconds(0));
    }

    public void Dispose()
    {
        _driver.Manage().Timeouts().ImplicitlyWait(TimeSpan.FromSeconds(30));
    }
}

回答4:

@Jonic's answer helped me, however I would add a try { } finally { } and call turnOnImplicitWaits() in the finally block to make sure it always turns back on.

protected boolean isElementHiddenNow(String id) {
    turnOffImplicitWaits();
    boolean result = false;
    try {
       result = ExpectedConditions.invisibilityOfElementLocated(By.id(id)).apply(driver);
    }
    finally {
       turnOnImplicitWaits();
    }
    return result;
}

回答5:

My approach was to bypass Implicit wait entirely and reimplement it (with an addition of a visibility check etc.) in my own findElement() and findElements() methods which I now use by default. This way, when I want to check something instantly, I can call the original WebDriver method which does, of course, not wait.

回答6:

In an existing code relying a lot on implicit wait way of thinking, and without CSS to the rescue, I found a way out nfor that kind of things, complementing it with Jsoup, and going on with Jsoup:

# this is straightforward Scala... put the types and it is Java.
val innerHtml = seleniumWebElementFatherInstance.getAttribute("innerHTML")
val jsoupElements = Jsoup.parse(innerHtml).select("div.your.css.selector")

来源：https://stackoverflow.com/questions/11034710/temporarily-bypassing-implicit-waits-with-webdriver