Custom ExpectedCondition in Selenium Java - Test Execution Trace

Test Overview

This test demonstrates how to create and use a custom ExpectedCondition in Selenium WebDriver with Java. It waits for a specific element's text to become "Loaded" before proceeding, verifying the page state dynamically.

Test Code - Selenium

Selenium Java

import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.support.ui.ExpectedCondition;
import org.openqa.selenium.support.ui.WebDriverWait;
import java.time.Duration;

public class CustomExpectedConditionTest {
    public static void main(String[] args) {
        System.setProperty("webdriver.chrome.driver", "/path/to/chromedriver");
        WebDriver driver = new ChromeDriver();
        try {
            driver.get("https://example.com/loadingpage");

            WebDriverWait wait = new WebDriverWait(driver, Duration.ofSeconds(10));

            ExpectedCondition<Boolean> textIsLoaded = new ExpectedCondition<Boolean>() {
                public Boolean apply(WebDriver d) {
                    WebElement element = d.findElement(By.id("status"));
                    return "Loaded".equals(element.getText());
                }

                public String toString() {
                    return "text to be 'Loaded' in element with id 'status'";
                }
            };

            wait.until(textIsLoaded);

            WebElement statusElement = driver.findElement(By.id("status"));
            assert "Loaded".equals(statusElement.getText()) : "Status text is not 'Loaded'";

            System.out.println("Test Passed: Status text is 'Loaded'.");
        } finally {
            driver.quit();
        }
    }
}

Execution Trace - 5 Steps

Step	Action	System State	Assertion	Result
1	Test starts and ChromeDriver is initialized	Browser window opens with a blank page	—	PASS
2	Navigates to https://example.com/loadingpage	Page loads with element id='status' showing initial text (e.g., 'Loading...')	—	PASS
3	Waits up to 10 seconds for element with id 'status' text to become 'Loaded' using custom ExpectedCondition	Page updates element text from 'Loading...' to 'Loaded' dynamically	Checks if element text equals 'Loaded'	PASS
4	Finds element with id 'status' and asserts its text is 'Loaded'	Element text is 'Loaded'	assert "Loaded".equals(statusElement.getText())	PASS
5	Prints success message and closes browser	Browser closes	—	PASS

Failure Scenario

Failing Condition: Element with id 'status' text does not become 'Loaded' within 10 seconds

Execution Trace Quiz - 3 Questions

What does the custom ExpectedCondition in this test check for?

A The element with id 'status' is visible

B The page URL contains 'loadingpage'

C The element with id 'status' has text 'Loaded'

D The element with id 'status' is clickable

Key Result

Creating custom ExpectedConditions allows precise waiting for specific page states, improving test reliability when built-in conditions are insufficient.

Practice

1. What is the main purpose of creating a Custom ExpectedCondition in Selenium Java?

easy

A. To automatically generate test reports

B. To replace the WebDriverWait class entirely

C. To speed up test execution by skipping waits

D. To define a specific condition that WebDriverWait will wait for before proceeding

Solution

1. Step 1: Understand the role of ExpectedCondition

   ExpectedCondition defines a condition that WebDriverWait checks repeatedly until it returns a non-null value or true.

2. Step 2: Purpose of Custom ExpectedCondition

   Creating a custom one allows you to specify your own logic for waiting, beyond built-in conditions.

3. Final Answer:

   To define a specific condition that WebDriverWait will wait for before proceeding -> Option D

4. Quick Check:

   Custom ExpectedCondition = Custom wait logic [OK]

Hint: Custom ExpectedCondition defines what to wait for [OK]

Common Mistakes:

• Thinking it replaces WebDriverWait
• Assuming it speeds up tests by skipping waits
• Confusing it with reporting features

2. Which method must be implemented when creating a custom ExpectedCondition in Selenium Java?

easy

A. apply(WebDriver driver)

B. waitForCondition()

C. checkCondition(WebElement element)

D. execute()

Solution

1. Step 1: Recall ExpectedCondition interface

   The ExpectedCondition interface requires implementing the apply method that takes a WebDriver and returns a result or null.

2. Step 2: Identify correct method name

   Only apply(WebDriver driver) is the correct method signature for custom conditions.

3. Final Answer:

   apply(WebDriver driver) -> Option A

4. Quick Check:

   Custom ExpectedCondition method = apply() [OK]

Hint: Custom ExpectedCondition always implements apply(driver) [OK]

Common Mistakes:

• Using wrong method names like waitForCondition or execute
• Confusing with WebElement methods
• Missing the WebDriver parameter

3. Given the following custom ExpectedCondition code snippet, what will be the output if the element with id 'status' has text 'Ready'?

ExpectedCondition<Boolean> condition = driver -> {
  WebElement el = driver.findElement(By.id("status"));
  return el.getText().equals("Ready") ? true : null;
};
WebDriverWait wait = new WebDriverWait(driver, Duration.ofSeconds(5));
boolean result = wait.until(condition);

medium

A. The code will cause a compilation error

B. The wait will pass and result will be true

C. The wait will pass and result will be null

D. The wait will timeout and throw TimeoutException

Solution

1. Step 1: Analyze the condition logic

   The condition returns true if the element's text equals "Ready", otherwise null.

2. Step 2: Understand WebDriverWait behavior

   WebDriverWait waits until the condition returns a non-null, true value. Since text is "Ready", condition returns true immediately.

3. Final Answer:

   The wait will pass and result will be true -> Option B

4. Quick Check:

   Condition true means wait passes [OK]

Hint: If condition returns true, wait.until returns true [OK]

Common Mistakes:

• Thinking null return means pass
• Assuming wait throws error on true
• Confusing null with false

4. Identify the error in this custom ExpectedCondition implementation:

ExpectedCondition<Boolean> condition = driver -> {
  WebElement el = driver.findElement(By.id("submit"));
  if(el.isDisplayed()) {
    return true;
  } else {
    return false;
  }
};

medium

A. findElement should be replaced with findElements

B. Using lambda expression is not allowed for ExpectedCondition

C. Returning false instead of null causes wait.until to stop waiting prematurely

D. Missing try-catch block for NoSuchElementException

Solution

1. Step 1: Understand ExpectedCondition return rules

   ExpectedCondition should return null to continue waiting, true to stop waiting successfully.

2. Step 2: Analyze the code's return values

   Returning false causes wait.until to stop waiting and throw TimeoutException immediately, which is not desired.

3. Final Answer:

   Returning false instead of null causes wait.until to stop waiting prematurely -> Option C

4. Quick Check:

   Return null to keep waiting, not false [OK]

Hint: Return null to wait longer, not false [OK]

Common Mistakes:

• Returning false instead of null to continue wait
• Assuming lambda is invalid
• Ignoring exception handling

5. You want to create a custom ExpectedCondition that waits until a list of elements with class 'item' contains at least 3 visible elements. Which implementation correctly achieves this?

hard

A. ExpectedCondition<Boolean> condition = driver -> {
List<WebElement> items = driver.findElements(By.className("item"));
long visibleCount = items.stream().filter(WebElement::isDisplayed).count();
return visibleCount >= 3 ? true : null;
};

B. ExpectedCondition<Boolean> condition = driver -> {
List<WebElement> items = driver.findElements(By.className("item"));
int count = 0;
for(WebElement item : items) {
if(item.isDisplayed()) count++;
}
return count > 3 ? true : false;
};

C. ExpectedCondition<Boolean> condition = driver -> {
List<WebElement> items = driver.findElements(By.className("item"));
return items.size() >= 3;
};

D. ExpectedCondition<Boolean> condition = driver -> {
List<WebElement> items = driver.findElements(By.className("item"));
return items.stream().allMatch(WebElement::isDisplayed);
};

Solution

1. Step 1: Understand the requirement

   Wait until at least 3 elements with class 'item' are visible (isDisplayed() true).

2. Step 2: Analyze each option

   ExpectedCondition<Boolean> condition = driver -> { List<WebElement> items = driver.findElements(By.className("item")); long visibleCount = items.stream().filter(WebElement::isDisplayed).count(); return visibleCount >= 3 ? true : null; }; counts visible elements and returns true if count >= 3, else null to keep waiting. This matches requirement and wait logic.
   ExpectedCondition<Boolean> condition = driver -> { List<WebElement> items = driver.findElements(By.className("item")); int count = 0; for(WebElement item : items) { if(item.isDisplayed()) count++; } return count > 3 ? true : false; }; returns false if count is not > 3, which stops wait prematurely.
   ExpectedCondition<Boolean> condition = driver -> { List<WebElement> items = driver.findElements(By.className("item")); return items.size() >= 3; }; checks total size, ignoring visibility.
   ExpectedCondition<Boolean> condition = driver -> { List<WebElement> items = driver.findElements(By.className("item")); return items.stream().allMatch(WebElement::isDisplayed); }; waits until all are visible, not at least 3.

3. Final Answer:

   Option A correctly waits for at least 3 visible elements -> Option A

4. Quick Check:

   Return true if condition met, else null to wait [OK]

Hint: Return true if condition met, else null to wait [OK]

Common Mistakes:

• Returning false instead of null to continue wait
• Ignoring visibility check
• Checking all elements visible instead of at least 3