When writing Selenium tests, is there an equivalent built-in functionality for waiting until elements appear or become visible?

General Discussions
#1

In HTML Selenium tests, commands like WaitForElementPresent or WaitForVisible are very useful for waiting until elements appear or become visible.

<tr>
    <td>waitForElementPresent</td>
    <td>id=saveButton</td>
    <td></td>
</tr>

However, when writing Selenium tests in Java using WebDriver (or Selenium RC), is there an equivalent built-in functionality?

For example, when verifying the visibility of a dialog that takes time to open:

WebElement dialog = driver.findElement(By.id("reportDialog"));
assertTrue(dialog.isDisplayed());  // Often fails as the dialog isn't visible *yet*

What’s the best way to robustly wait until an element is visible in such scenarios?

Using Thread.sleep() throughout the code would be inelegant and fragile. Creating custom while loops seems cumbersome. What’s the cleanest approach to handle Selenium wait until element is visible in Java tests?

#2

An implicit wait directs WebDriver to poll the DOM for a specified amount of time when trying to locate an element. If the element is not immediately available, WebDriver will wait for the defined duration before throwing an exception.

By default, the implicit wait is set to 0 seconds. Once set, it remains effective for the entire lifespan of the WebDriver object instance.

Example of setting an implicit wait for 10 seconds:

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

Explicit Wait + Expected Conditions:

Explicit waits are code structures you define to wait for a specific condition to be met before proceeding further in the code execution. Unlike implicit waits, explicit waits are more flexible and responsive, avoiding the need to wait for a fixed time duration like Thread.sleep().

One effective way to implement an explicit wait is using WebDriverWait in combination with ExpectedConditions. This approach allows WebDriver to wait dynamically until the expected condition (such as visibility of an element) is met or a timeout occurs.

Example using WebDriverWait to wait until an element with id “someid” becomes visible:

WebDriverWait wait = new WebDriverWait(driver, 10);
WebElement element = wait.until(ExpectedConditions.visibilityOfElementLocated(By.id("someid")));

In this example:

WebDriverWait is instantiated with a timeout of 10 seconds (new WebDriverWait(driver, 10)). ExpectedConditions.visibilityOfElementLocated(By.id(“someid”)) specifies the condition to wait for—visibility of the element identified by “someid”.

The wait.until() method waits until the expected condition returns a non-null value (indicating the condition is met) or throws a TimeoutException if the condition is not met within the specified timeout period.

Using explicit waits with ExpectedConditions enhances test reliability by allowing WebDriver to synchronize with the application’s dynamic behavior, making tests more robust and less prone to timing issues compared to using implicit waits or fixed sleep times.

#3

Another method to wait for a maximum of 10 seconds for an element to be displayed is demonstrated below:

(new WebDriverWait(driver, 10)).until(new ExpectedCondition<Boolean>() {
    public Boolean apply(WebDriver d) {
        return d.findElement(By.id("<name>")).isDisplayed();
    }
});

In this code:

WebDriverWait is instantiated with a timeout of 10 seconds (new WebDriverWait(driver, 10)). ExpectedCondition is used to define a condition (apply()) that WebDriver will wait for. The condition checks if the element identified by its id (“”) is displayed (isDisplayed() method).

This approach ensures that WebDriver waits dynamically until the element is displayed or until the timeout period of 10 seconds expires. It’s a flexible and reliable way to synchronize test execution with the application’s state, avoiding unnecessary delays and enhancing test reliability.

#4

The preferred method is to use Explicit Wait (WebDriverWait) instead of using Thread.sleep(). Based on your feedback, I have refactored the code to improve readability by adding curly braces around the if statement. Thank you for your input.

Example using WebDriverWait to wait for an element to be displayed for a maximum of 10 seconds:

WebDriverWait wait = new WebDriverWait(driver, 10);
wait.until(new ExpectedCondition<Boolean>() {
    public Boolean apply(WebDriver driver) {
        return driver.findElement(By.id("<name>")).isDisplayed();
    }
});

In this example:

WebDriverWait is instantiated with a timeout of 10 seconds (new WebDriverWait(driver, 10)). The until() method waits until the condition defined inside apply() returns true, indicating that the element identified by By.id(“”) is displayed. Using ExpectedCondition() allows you to define custom conditions that WebDriver waits for, enhancing the robustness and reliability of your tests compared to using Thread.sleep().

By using Explicit Wait (WebDriverWait) you can use Selenium wait until element is visible easily.