findElement by cssSelector in Selenium Java - Test Execution Trace

Test Overview

This test opens a web page, finds a button using a CSS selector, clicks it, and verifies the button's text changes as expected.

Test Code - JUnit with Selenium WebDriver

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.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertEquals;

public class CssSelectorTest {
    private WebDriver driver;

    @BeforeEach
    public void setUp() {
        driver = new ChromeDriver();
    }

    @Test
    public void testFindElementByCssSelector() {
        driver.get("https://example.com/buttonpage");
        WebElement button = driver.findElement(By.cssSelector("button#submit-btn.primary"));
        button.click();
        String buttonText = button.getText();
        assertEquals("Submitted", buttonText);
    }

    @AfterEach
    public void tearDown() {
        if (driver != null) {
            driver.quit();
        }
    }
}

Execution Trace - 6 Steps

Step	Action	System State	Assertion	Result
1	Test starts and Chrome browser opens	Chrome browser window is open and ready	—	PASS
2	Navigate to URL https://example.com/buttonpage	Browser displays the page with a button having id 'submit-btn' and class 'primary'	—	PASS
3	Find element using CSS selector 'button#submit-btn.primary'	Button element located on the page	Element is found and is a button with correct id and class	PASS
4	Click the found button element	Button is clicked, triggering page or element update	—	PASS
5	Get text of the button after click	Button text is now 'Submitted'	Assert that button text equals 'Submitted'	PASS
6	Test ends and browser closes	Browser window is closed	—	PASS

Failure Scenario

Failing Condition: The CSS selector does not match any element on the page

Execution Trace Quiz - 3 Questions

What does the CSS selector 'button#submit-btn.primary' select?

A A button element with id 'submit-btn' and class 'primary'

B Any element with id 'submit-btn' or class 'primary'

C Any button element with class 'submit-btn' and id 'primary'

D A div element with id 'submit-btn' and class 'primary'

Key Result

Use precise CSS selectors combining tag, id, and class to reliably find elements. Always assert expected changes after interactions.

Practice

1. What does driver.findElement(By.cssSelector(".btn-primary")) do in Selenium Java?

easy

A. Finds all elements with class 'btn-primary' on the page

B. Finds the first element with class 'btn-primary' on the page

C. Finds the element with id 'btn-primary'

D. Throws an error if any element has class 'btn-primary'

Solution

1. Step 1: Understand the method used

   findElement returns the first matching element found on the page.

2. Step 2: Analyze the CSS selector

   The selector .btn-primary matches elements with class btn-primary.

3. Final Answer:

   Finds the first element with class 'btn-primary' on the page -> Option B

4. Quick Check:

   findElement + .class = first matching element [OK]

Hint: findElement + .class finds first element with that class [OK]

Common Mistakes:

• Confusing findElement with findElements
• Using id selector syntax for class
• Thinking it finds all matching elements

2. Which of the following is the correct syntax to find an element with id 'login' using CSS selector in Selenium Java?

easy

A. driver.findElement(By.cssSelector(".login"));

B. driver.findElement(By.cssSelector("*login"));

C. driver.findElement(By.cssSelector("login"));

D. driver.findElement(By.cssSelector("#login"));

Solution

1. Step 1: Identify CSS selector for id

   In CSS, id selectors start with #, so #login selects element with id 'login'.

2. Step 2: Check syntax correctness

   The syntax driver.findElement(By.cssSelector("#login")); is correct for Selenium Java.

3. Final Answer:

   driver.findElement(By.cssSelector("#login")); -> Option D

4. Quick Check:

   Id selector uses # [OK]

Hint: Use # for id selectors in CSS [OK]

Common Mistakes:

• Using . instead of # for id
• Missing quotes around selector
• Using invalid selector syntax

3. What will be the result of this code snippet?

WebElement element = driver.findElement(By.cssSelector("div.content > p.highlight"));
String text = element.getText();
System.out.println(text);

Assuming the HTML is:

<div class="content">
  <p class="highlight">Hello</p>
  <p>World</p>
</div>

medium

A. HelloWorld

B. World

C. Hello

D. NoSuchElementException

Solution

1. Step 1: Understand the CSS selector used

   div.content > p.highlight selects a p element with class highlight that is a direct child of div with class content.

2. Step 2: Match selector to HTML

   The first p inside div.content has class highlight and text "Hello".

3. Final Answer:

   Hello -> Option C

4. Quick Check:

   Selector matches first p.highlight text [OK]

Hint: Use > for direct child in CSS selectors [OK]

Common Mistakes:

• Ignoring direct child combinator >
• Selecting wrong paragraph text
• Assuming all p tags are selected

4. Identify the error in this Selenium Java code:

WebElement button = driver.findElement(By.cssSelector("button#submit-btn.active"));
button.click();

Given the HTML:

<button id="submit-btn">Submit</button>

medium

A. CSS selector requires both id and class but element has no class 'active'

B. Syntax error in findElement method call

C. button.click() is invalid method

D. NoSuchElementException because id selector is wrong

Solution

1. Step 1: Analyze the CSS selector

   The selector button#submit-btn.active looks for a button with id submit-btn AND class active.

2. Step 2: Compare with HTML element

   The button has id submit-btn but no class active, so selector matches no element.

3. Final Answer:

   CSS selector requires both id and class but element has no class 'active' -> Option A

4. Quick Check:

   Selector requires all parts to match [OK]

Hint: All parts in CSS selector must match element attributes [OK]

Common Mistakes:

• Assuming partial match works in CSS selector
• Ignoring missing class in element
• Thinking click() method is invalid

5. You want to find the first input element inside a form with class 'search' that is enabled and visible. Which CSS selector is best to use with findElement in Selenium Java?

hard

A. form.search input:not([disabled])

B. form.search > input[disabled='false']

C. form.search input:enabled

D. form.search input[visible='true']

Solution

1. Step 1: Understand CSS selectors for enabled inputs

   CSS does not have a standard :enabled pseudo-class for all browsers; instead, :not([disabled]) selects inputs without the disabled attribute.

2. Step 2: Check options for correctness

   form.search input:enabled uses :enabled which is not widely supported in CSS selectors for Selenium.
   form.search > input[disabled='false'] uses attribute [disabled='false'] which is invalid because disabled is boolean attribute.
   form.search input:not([disabled]) uses :not([disabled]) which correctly selects enabled inputs.
   form.search input[visible='true'] uses [visible='true'] which is not a valid attribute for visibility.

3. Final Answer:

   form.search input:not([disabled]) -> Option A

4. Quick Check:

   Use :not([disabled]) to find enabled inputs [OK]

Hint: Use :not([disabled]) to select enabled inputs [OK]

Common Mistakes:

• Using unsupported :enabled pseudo-class
• Checking disabled='false' attribute incorrectly
• Using non-existent visible attribute