CSS attribute selectors in Selenium Python - Test Execution Trace

Test Overview

This test opens a webpage and uses a CSS attribute selector to find an input element with a specific placeholder attribute. It verifies that the input box is present and can be interacted with.

Test Code - Selenium

Selenium Python

from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
import unittest

class TestCSSAttributeSelector(unittest.TestCase):
    def setUp(self):
        self.driver = webdriver.Chrome()
        self.driver.get('https://example.com/form')

    def test_input_with_placeholder(self):
        driver = self.driver
        # Wait until the input with placeholder 'Enter your name' is present
        input_element = WebDriverWait(driver, 10).until(
            EC.presence_of_element_located((By.CSS_SELECTOR, "input[placeholder='Enter your name']"))
        )
        # Check if the input is displayed
        self.assertTrue(input_element.is_displayed())
        # Enter text into the input
        input_element.send_keys('Alice')
        # Verify the entered text
        self.assertEqual(input_element.get_attribute('value'), 'Alice')

    def tearDown(self):
        self.driver.quit()

if __name__ == '__main__':
    unittest.main()

Execution Trace - 6 Steps

Step	Action	System State	Assertion	Result
1	Test starts and Chrome browser opens	Browser window is open and navigated to https://example.com/form	—	PASS
2	Wait until input element with placeholder 'Enter your name' is present using CSS attribute selector	Page loaded with form containing input fields	Presence of element located by CSS selector input[placeholder='Enter your name']	PASS
3	Check if the input element is displayed	Input element is visible on the page	input_element.is_displayed() returns True	PASS
4	Send keys 'Alice' to the input element	Input element now contains text 'Alice'	—	PASS
5	Verify the input element's value attribute equals 'Alice'	Input element's value attribute is 'Alice'	input_element.get_attribute('value') == 'Alice'	PASS
6	Close the browser and end the test	Browser closed	—	PASS

Failure Scenario

Failing Condition: The input element with placeholder 'Enter your name' is not found within 10 seconds

Execution Trace Quiz - 3 Questions

Which CSS selector is used to find the input element in this test?

A input#name

B input[placeholder='Enter your name']

C input.classname

D input[type='text']

Key Result

Using CSS attribute selectors allows precise targeting of elements by their attributes, which is useful when IDs or classes are not unique or available.

Practice

1. What does the CSS selector input[type='text'] select in Selenium?

easy

A. All input elements regardless of type

B. All elements with any attribute containing 'text'

C. All elements with class 'text'

D. All input elements with type attribute exactly equal to 'text'

Solution

1. Step 1: Understand the attribute selector syntax

   The selector input[type='text'] targets input tags with an attribute type exactly equal to 'text'.

2. Step 2: Match the selector meaning to options

   All input elements with type attribute exactly equal to 'text' correctly describes this exact match. Other options describe different or incorrect matches.

3. Final Answer:

   All input elements with type attribute exactly equal to 'text' -> Option D

4. Quick Check:

   Exact attribute match = C [OK]

Hint: Exact match uses [attr='value'] syntax [OK]

Common Mistakes:

• Confusing exact match with partial match
• Selecting wrong tag type
• Mixing class selectors with attribute selectors

2. Which of the following is the correct CSS selector to find elements with an attribute data-id that starts with 'user'?

easy

A. [data-id^='user']

B. [data-id*='user']

C. [data-id$='user']

D. [data-id='user']

Solution

1. Step 1: Recall CSS attribute selectors for matching start of value

   The caret symbol ^= means 'starts with' in CSS attribute selectors.

2. Step 2: Match the selector to the question

   [data-id^='user'] uses [data-id^='user'], which selects elements whose data-id attribute starts with 'user'.

3. Final Answer:

   [data-id^='user'] -> Option A

4. Quick Check:

   Starts with selector = B [OK]

Hint: Use ^= for 'starts with' attribute matching [OK]

Common Mistakes:

• Using *= instead of ^= for starts with
• Using $= which means ends with
• Using exact match = instead of partial

3. What will the following Selenium Python code print if the page has three <input> elements with name attributes: 'user1', 'user2', and 'admin'?

elements = driver.find_elements(By.CSS_SELECTOR, "input[name*='user']")
print(len(elements))

medium

A. 2

B. 3

C. 1

D. 0

Solution

1. Step 1: Understand the CSS selector input[name*='user']

   This selector finds input elements whose name attribute contains the substring 'user'.

2. Step 2: Count matching elements

   Given names 'user1', 'user2', and 'admin', only 'user1' and 'user2' contain 'user'. So, 2 elements match.

3. Final Answer:

   2 -> Option A

4. Quick Check:

   Substring match count = 2 [OK]

Hint: Use *= to find attributes containing substring [OK]

Common Mistakes:

• Counting all inputs instead of filtered ones
• Confusing starts with (^) and contains (*) selectors
• Assuming exact match instead of partial

4. You wrote this Selenium code but it throws an error:

element = driver.find_element(By.CSS_SELECTOR, "button[class^='submit']'")

What is the error and how to fix it?

medium

A. Wrong attribute selector; use *= instead of ^=

B. Extra single quote at the end; remove it to fix

C. Missing tag name before attribute selector

D. CSS selector cannot use ^ for attribute matching

Solution

1. Step 1: Inspect the CSS selector string syntax

   The selector ends with an extra single quote after the closing double quote: "button[class^='submit']'". This causes a syntax error.

2. Step 2: Correct the string by removing the extra quote

   Removing the extra single quote at the end fixes the syntax: "button[class^='submit']".

3. Final Answer:

   Extra single quote at the end; remove it to fix -> Option B

4. Quick Check:

   Check quotes balance = A [OK]

Hint: Check for balanced quotes in selectors [OK]

Common Mistakes:

• Ignoring syntax errors caused by quotes
• Changing correct attribute selectors unnecessarily
• Assuming CSS does not support ^= selector

5. You want to select all <a> tags whose href attribute ends with '.pdf' or '.docx' using a single CSS selector in Selenium. Which selector is correct?

hard

A. a[href*='.pdf' or '.docx']

B. a[href$='.pdf' || href$='.docx']

C. a[href$='.pdf'], a[href$='.docx']

D. a[href$='.pdf'][href$='.docx']

Solution

1. Step 1: Understand CSS selector for multiple attribute matches

   To select elements matching either condition, use a comma to separate selectors: a[href$='.pdf'], a[href$='.docx'].

2. Step 2: Analyze other options for correctness

   a[href$='.pdf' || href$='.docx'] uses invalid syntax with || inside attribute selector. a[href$='.pdf'][href$='.docx'] requires both endings simultaneously, impossible. a[href*='.pdf' or '.docx'] uses invalid syntax with 'or'.

3. Final Answer:

   a[href$='.pdf'], a[href$='.docx'] -> Option C

4. Quick Check:

   Use comma to combine selectors = D [OK]

Hint: Combine selectors with comma for OR conditions [OK]

Common Mistakes:

• Using logical operators inside attribute selectors
• Trying to combine multiple attribute endings in one selector without comma
• Assuming multiple attribute selectors mean OR instead of AND