Network log capture in Selenium Python - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is network log capture in Selenium testing?

Network log capture is the process of recording all network requests and responses made by the browser during a test. It helps testers see what data is sent and received, like a phone call record for the browser.

intermediate

Which Selenium feature allows capturing network logs in Python?

Using Selenium with Chrome DevTools Protocol (CDP) allows capturing network logs. You enable performance logging in Chrome options and then access logs via Selenium's driver.get_log('performance').

beginner

Why is capturing network logs useful in testing?

It helps verify if the right API calls are made, check response data, find slow requests, and detect errors invisible on the page. Like checking the mailman’s delivery to ensure messages arrived correctly.

intermediate

How do you enable performance logging in ChromeDriver for Selenium Python?

You create ChromeOptions, add the experimental option 'perfLoggingPrefs' with {'enableNetwork': True}, and set 'loggingPrefs' in capabilities to enable performance logging. Then pass these options and capabilities to ChromeDriver.

beginner

What kind of information can you find in network logs captured during Selenium tests?

You can find request URLs, HTTP methods, status codes, headers, request and response bodies, and timing details. This helps understand what data the browser exchanged with servers.

What is the main purpose of capturing network logs in Selenium tests?

A To change the browser's UI

B To speed up the test execution

C To see all network requests and responses during the test

D To write test cases automatically

Network logs show all network activity, helping testers verify data exchange.

Which Selenium driver supports capturing network logs via Chrome DevTools Protocol?

A FirefoxDriver

B ChromeDriver

C EdgeDriver

D SafariDriver

ChromeDriver supports CDP which allows network log capture.

How do you access network logs in Selenium Python after enabling performance logging?

A driver.get_log('performance')

B driver.get_log('network')

C driver.get_network_logs()

D driver.get_logs()

Performance logs include network events and are accessed with 'performance'.

Which of these is NOT typically found in network logs?

A HTTP status codes

B Request URLs

C Request and response headers

D Browser UI layout

Network logs do not include browser UI layout information.

Why might a tester want to check network logs during a test?

A To verify API calls and responses

B To change the test script automatically

C To speed up page loading

D To change browser settings

Checking API calls and responses helps ensure correct backend communication.

Explain how to enable and capture network logs in Selenium using Python and ChromeDriver.

Think about Chrome DevTools Protocol and performance logs.

Describe why network log capture is important in software testing and what information it provides.

Consider how network logs help understand backend communication.

Practice

1. What is the main purpose of capturing network logs in Selenium tests?

easy

A. To see the communication between browser and server during tests

B. To speed up the test execution time

C. To change the browser's UI elements

D. To generate random test data automatically

Solution

1. Step 1: Understand network logs in Selenium

   Network logs capture the details of requests and responses between the browser and server during test execution.

2. Step 2: Identify the main purpose

   This helps testers verify if the correct URLs are called and if responses are successful.

3. Final Answer:

   To see the communication between browser and server during tests -> Option A

4. Quick Check:

   Network logs show browser-server communication [OK]

Hint: Network logs = browser-server communication details [OK]

Common Mistakes:

• Thinking network logs speed up tests
• Confusing UI changes with network logs
• Assuming network logs generate test data

2. Which Chrome option enables performance logging to capture network events in Selenium?

easy

A. "args": ["--disable-extensions"]

B. "goog:loggingPrefs": {"performance": "ALL"}

C. "prefs": {"download.default_directory": "/tmp"}

D. "chromeOptions": {"headless": true}

Solution

1. Step 1: Identify the correct Chrome option for logging

   Performance logging is enabled by setting "goog:loggingPrefs" with "performance" set to "ALL".

2. Step 2: Understand other options

   Other options like headless mode or disabling extensions do not enable network log capture.

3. Final Answer:

   "goog:loggingPrefs": {"performance": "ALL"} -> Option B

4. Quick Check:

   Enable performance logs with goog:loggingPrefs [OK]

Hint: Use goog:loggingPrefs with performance ALL to capture network logs [OK]

Common Mistakes:

• Confusing headless mode with logging
• Using download preferences for network logs
• Disabling extensions instead of enabling logs

3. Given this code snippet, what will be printed?

logs = driver.get_log('performance')
for entry in logs:
    message = json.loads(entry['message'])['message']
    if message['method'] == 'Network.responseReceived':
        print(message['params']['response']['url'])

medium

A. All browser console error messages

B. Only URLs of failed network requests

C. All URLs of network responses received during the test

D. List of all clickable elements on the page

Solution

1. Step 1: Understand the log parsing code

   The code reads performance logs, filters for 'Network.responseReceived' events, and prints the response URLs.

2. Step 2: Identify what is printed

   It prints all URLs for network responses received, regardless of success or failure.

3. Final Answer:

   All URLs of network responses received during the test -> Option C

4. Quick Check:

   Code prints URLs from Network.responseReceived events [OK]

Hint: Network.responseReceived logs contain all response URLs [OK]

Common Mistakes:

• Assuming only failed URLs are printed
• Confusing network logs with console errors
• Thinking it lists page elements

4. What is wrong with this code snippet for capturing network logs?

options = webdriver.ChromeOptions()
options.set_capability('loggingPrefs', {'performance': 'ALL'})
driver = webdriver.Chrome(options=options)
logs = driver.get_log('performance')

medium

A. The capability key should be 'goog:loggingPrefs', not 'loggingPrefs'

B. The ChromeOptions object cannot be used with Chrome driver

C. The get_log method does not exist in Selenium

D. Performance logs cannot be captured in Chrome

Solution

1. Step 1: Check capability key correctness

   The correct key to enable performance logging is 'goog:loggingPrefs', not 'loggingPrefs'.

2. Step 2: Verify other statements

   ChromeOptions can be used with Chrome driver, get_log exists, and performance logs can be captured.

3. Final Answer:

   The capability key should be 'goog:loggingPrefs', not 'loggingPrefs' -> Option A

4. Quick Check:

   Use 'goog:loggingPrefs' to enable performance logs [OK]

Hint: Use 'goog:loggingPrefs' key for performance logging [OK]

Common Mistakes:

• Using wrong capability key
• Thinking ChromeOptions is incompatible
• Believing get_log method is missing

5. How can you verify in Selenium that a specific API call to 'https://api.example.com/data' returned status code 200 using network logs?

hard

A. Use driver.execute_script to intercept network calls directly

B. Use driver.get_log('browser') and search for the URL string

C. Check page source for the URL and assume status 200 if found

D. Parse performance logs, find 'Network.responseReceived' events, check if response URL matches and status is 200

Solution

1. Step 1: Capture and parse performance logs

   Enable performance logging and get logs with driver.get_log('performance').

2. Step 2: Filter 'Network.responseReceived' events and check URL and status

   Look for events where response URL matches 'https://api.example.com/data' and verify status code is 200.

3. Final Answer:

   Parse performance logs, find 'Network.responseReceived' events, check if response URL matches and status is 200 -> Option D

4. Quick Check:

   Check responseReceived events for URL and status 200 [OK]

Hint: Filter Network.responseReceived logs by URL and status code [OK]

Common Mistakes:

• Using browser logs instead of performance logs
• Assuming URL presence means status 200
• Trying to intercept network calls with execute_script