File download handling in Selenium Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Selenium Python code snippet for file download?

Consider the following Selenium Python code that sets up a Firefox profile to automatically download PDF files without showing the download dialog. What will be the value of download_dir after the code runs?

Selenium Python

from selenium import webdriver
from selenium.webdriver.firefox.options import Options

options = Options()
profile = webdriver.FirefoxProfile()
download_dir = '/tmp/downloads'
profile.set_preference('browser.download.folderList', 2)
profile.set_preference('browser.download.dir', download_dir)
profile.set_preference('browser.helperApps.neverAsk.saveToDisk', 'application/pdf')
profile.set_preference('pdfjs.disabled', True)
driver = webdriver.Firefox(firefox_profile=profile, options=options)

print(download_dir)

A /home/user/downloads

B browser.download.dir

C /tmp/downloads

D None

💡 Hint

Look at the variable assigned to download_dir and what is printed.

The variable download_dir is set to the string '/tmp/downloads' and then printed. The Selenium preferences use this variable but do not change its value.

❓ assertion

intermediate

Which assertion correctly verifies a file was downloaded?

You want to check if a file named 'report.pdf' exists in the download directory after triggering a download in Selenium Python. Which assertion is correct?

Selenium Python

import os
file_path = '/tmp/downloads/report.pdf'

# Which assertion below correctly checks the file exists?

A assert os.path.isfile(file_path)

B assert os.path.exists(file_path) == False

C assert os.path.isdir(file_path)

D assert file_path in os.listdir('/tmp/downloads') == False

💡 Hint

Use the function that checks if a path is a file.

os.path.isfile(file_path) returns True if the path exists and is a file. This is the correct way to assert the file was downloaded.

🔧 Debug

advanced

Why does this Selenium Python code fail to download the file automatically?

This code is intended to download CSV files automatically without a dialog, but the download dialog still appears. What is the likely cause?

Selenium Python

from selenium import webdriver
profile = webdriver.FirefoxProfile()
profile.set_preference('browser.download.folderList', 2)
profile.set_preference('browser.download.dir', '/tmp/downloads')
profile.set_preference('browser.helperApps.neverAsk.saveToDisk', 'text/csv')
driver = webdriver.Firefox(firefox_profile=profile)
driver.get('http://example.com/download.csv')

A FirefoxProfile is deprecated and ignored in recent Selenium versions

B Incorrect MIME type in 'neverAsk.saveToDisk' preference

C Missing setting to disable built-in PDF viewer

D Download directory path must be absolute

💡 Hint

Check if FirefoxProfile is still supported in recent Selenium versions.

Recent Selenium versions deprecate FirefoxProfile usage. The profile settings may be ignored, causing the download dialog to appear.

🧠 Conceptual

advanced

What is the best way to wait for a file download to complete in Selenium Python?

You trigger a file download in Selenium Python. The file may take some seconds to appear in the download folder. Which approach best waits for the download to finish?

A Use time.sleep(10) to wait a fixed time before checking the file

B Check the browser console logs for download completion message

C Use Selenium explicit waits on the download button element

D Poll the download folder checking for the file existence and size stability

💡 Hint

Waiting for file size to stop changing is a reliable method.

Polling the folder and checking that the file exists and its size does not change over a short period ensures the download is complete.

❓ framework

expert

How to configure ChromeDriver in Selenium Python to download files without prompt?

You want to configure ChromeDriver to download files automatically to '/tmp/downloads' without showing the download prompt. Which code snippet correctly sets this up?

A

from selenium import webdriver
options = webdriver.ChromeOptions()
options.set_preference('download.default_directory', '/tmp/downloads')
options.set_preference('download.prompt_for_download', False)
driver = webdriver.Chrome(options=options)

B

from selenium import webdriver
options = webdriver.ChromeOptions()
prefs = {'download.default_directory': '/tmp/downloads', 'download.prompt_for_download': False}
options.add_experimental_option('prefs', prefs)
driver = webdriver.Chrome(options=options)

C

from selenium import webdriver
prefs = {'download.default_directory': '/tmp/downloads', 'download.prompt_for_download': False}
driver = webdriver.Chrome(prefs=prefs)

D

from selenium import webdriver
options = webdriver.ChromeOptions()
options.add_argument('--download.default_directory=/tmp/downloads')
driver = webdriver.Chrome(options=options)

💡 Hint

ChromeOptions uses add_experimental_option to set preferences.

ChromeOptions requires adding preferences via add_experimental_option with a dictionary of prefs. Other methods are invalid or ignored.