YOU ARE DOING IT WRONG ALL THE TIME

The Great Battle of Selenium Waits

Speaker Info

Yaroslav Pernerovsky, Ukraine

Automation Team Lead,

GlobalLogic

/in/yaroslav-pernerovsky-0559b51

/yaroslav.pernerovsky

Problem

Implicit waits are a terrible mistake I've made and I apologies for them

Simon Stewart, d Creator of WebDriver

Problem

Problem

Problem

Problem

@Test

public void simpleAction() {

driver.get("http://www.google.com");

driver.findElement(By.name("q"))

.sendKeys("Search String" + Keys.ENTER);

driver.findElement(By.cssSelector("h3.r"))

.click();

}

Real Case

Real Case

Real Case

Custom Wait

while(true) {

if (System.currentTimeMillis()-startTime > timeout){

throw new TimeoutException();

}

try {

return driver.findElement(locator);

}

catch (NoSuchElementException e) {}

Thread.sleep(500);

}

WebDriver waits

chromedriver

geckodriver

IEDriverServer

Implicit waits here Explicit waits here

Implicit Waits

driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);

driver.manage().timeouts().pageLoadTimeout(10, TimeUnit.SECONDS);

driver.manage().timeouts().setScriptTimeout(10, TimeUnit.SECONDS);

Implicit Waits

driver.findElement()

• Wait until element appeared in DOM

• Return first element if more than one present

• Throws NoSuchElementException

Implicit Waits

driver.findElements()

• Wait until at least one element appeared in DOM

• Return collection of all found elements

• Return empty collection if no elements found

Implicit Waits Common Issue

public boolean isElementPresent(By locator) {

return driver.findElements(locator).size() > 0;

}

if (isElementPresent(login))

driver.findElement(login).click();

if (!isElementPresent(login))

driver.findElement(logout).click();

Implicit Waits Common Issue

public boolean isElementNotPresent(By locator) {

driver.manage().timeouts()

.implicitlyWait(0, TimeUnit.SECONDS);

boolean result= driver.findElements(locator).size() > 0;

driver.manage().timeouts()

.implicitlyWait(defaultTimeOut, TimeUnit.SECONDS);

return result;

}

Explicit Waits

WebDriverWait wait = new

WebDriverWait(driver, 10);

wait.until(driver ->

driver.findElement(locator));

wait.until(ExpectedConditions

.presenceOfElementLocated(locator));

http://seleniumhq.github.io/selenium/docs/api/java/org/openqa/selenium/support/ui/ExpectedConditions.html

What's wrong?

wait.until(driver ->

driver.findElement(locator));

WebDriver Exceptions and RemoteWebDriver

Solution?

wait.until(driver ->

driver.findElements(locator).size() > 0);

Mixed waits issues

What if?

wait = new WebDriverWait(driver,5);

driver.manage().timeouts()

.implicitlyWait(10, TimeUnit.SECONDS);

wait.until(ExpectedConditions

.presenceOfElementLocated(locator);

How long will Selenium wait ?

5 15

C: 10 25

Why?

public static ExpectedCondition<WebElement> presenceOfElementLocated(final By locator) {

return new ExpectedCondition<WebElement>() {

@Override

public WebElement apply(WebDriver driver) {

return findElement(locator, driver);

}

...

private static WebElement findElement(By by, WebDriver driver) {

try {

return driver.findElements(by).stream().findFirst().orElseThrow(

() -> new NoSuchElementException("Cannot locate an element using " + by));

} catch (NoSuchElementException e) {

throw e;

} catch (WebDriverException e) {

log.log(Level.WARNING,

String.format("WebDriverException thrown by findElement(%s)", by), e);

throw e;

}

}

What if?

wait = new WebDriverWait(driver,5);

driver.manage().timeouts()

.implicitlyWait(10, TimeUnit.SECONDS);

wait.until(ExpectedConditions

.presenceOfElementLocated(locator);

Which exception will be thrown ?

A: Timeout NoSuchElement

Both None

What if?

wait = new WebDriverWait(driver,10);

driver.manage().timeouts()

.implicitlyWait(5, TimeUnit.SECONDS);

wait.until(ExpectedConditions

.presenceOfElementLocated(locator);

How long will Selenium wait ?

5 15

C: 10 25

What if?

wait = new WebDriverWait(driver,11);

driver.manage().timeouts()

.implicitlyWait(5, TimeUnit.SECONDS);

wait.until(ExpectedConditions

.presenceOfElementLocated(locator);

How long will Selenium wait ?

5 B: 15

11 26

What if?

wait = new WebDriverWait(driver,5);

driver.manage().timeouts()

.implicitlyWait(10, TimeUnit.SECONDS);

wait.until(ExpectedConditions.not(

ExpectedConditions.presenceOfElementLocated(locator));

How long will Selenium wait if element is present?

A: 5 15

10 25

What if?

wait = new WebDriverWait(driver,5);

driver.manage().timeouts()

.implicitlyWait(10, TimeUnit.SECONDS);

wait.until(ExpectedConditions.not(

ExpectedConditions.presenceOfElementLocated(locator));

How long will Selenium wait if element is not present?

C:

5 15

10 25

Coexistence rules

Use Implicit wait for element presence

Do not use Explicit wait for element presence

Always set implicit timeout lower than explicit

Timeouts must be multiple to each other

Take special care to 'not present' conditions

Side-by-Side comparison

Client Side (500ms) Can wait for anything Explicit usage TimeoutException Multiple network calls

Explicit Implicit

Driver Side (100ms)

Element appeared in DOM Works automatically NoSuchElementException Single network call

Few words about Selenide

WebDriver Implicit Wait not used at all

Custom implicit waits on client side

Default polling interval - 100ms

Remote WebDriver traffic issues

Questions