Reading test data from JSON in Selenium Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of reading JSON test data in Selenium Python

What will be the output of the following code snippet that reads test data from a JSON file and prints the username?

Selenium Python

import json
with open('testdata.json', 'r') as file:
    data = json.load(file)
print(data['user']['username'])

A admin_user

B KeyError

C TypeError

D FileNotFoundError

💡 Hint

Check the JSON structure and the key used to access the username.

The code reads the JSON file and accesses the nested key 'user' then 'username'. If the JSON file contains {"user": {"username": "admin_user"}}, it prints 'admin_user'.

❓ assertion

intermediate

Correct assertion for JSON test data in Selenium Python

Which assertion correctly verifies that the password read from JSON test data equals 'pass123'?

Selenium Python

import json
with open('testdata.json', 'r') as file:
    data = json.load(file)
password = data['user']['password']

A assert password = 'pass123'

B assertEqual(password, 'pass123')

C assert password == 'pass123'

D assert password != 'pass123'

💡 Hint

Remember the correct syntax for assertions in Python.

Option C uses the correct Python assert statement syntax to check equality. Option C uses assignment instead of comparison, causing a syntax error. Option C is a unittest method but not used standalone. Option C asserts inequality, which is incorrect.

❓ locator

advanced

Best locator to use with JSON test data for Selenium Python

Given JSON test data contains a field 'login_button_id' with value 'btnLogin'. Which locator is best to find the login button in Selenium Python?

Selenium Python

login_button_id = data['login_button_id']

A driver.find_element(By.NAME, login_button_id)

B driver.find_element(By.CLASS_NAME, login_button_id)

C driver.find_element(By.XPATH, login_button_id)

D driver.find_element(By.ID, login_button_id)

💡 Hint

Consider the type of locator that matches an element's id attribute.

Since the JSON field contains the id of the button, using By.ID with that value is the most direct and reliable locator. Other options use different attributes that may not match the id value.

🔧 Debug

advanced

Identify the error when reading JSON test data

What error will this code raise if the JSON file is empty or malformed? import json with open('testdata.json', 'r') as file: data = json.load(file) print(data)

A FileNotFoundError

B json.decoder.JSONDecodeError

C KeyError

D TypeError

💡 Hint

Think about what happens when json.load tries to parse invalid JSON.

If the JSON file is empty or malformed, json.load raises JSONDecodeError indicating it cannot parse the content. FileNotFoundError occurs if the file is missing, KeyError if accessing missing keys, TypeError if wrong types are used.

❓ framework

expert

Best practice for integrating JSON test data in Selenium Python tests

Which approach best integrates JSON test data into Selenium Python tests for maintainability and reusability?

A Load JSON data once in a fixture or setup method and pass it to test functions

B Read the JSON file inside every test function separately

C Use global variables to store JSON data and access them anywhere

D Hardcode test data inside test functions instead of JSON

💡 Hint

Think about avoiding repeated file reads and keeping tests clean.

Loading JSON data once in a fixture or setup method improves efficiency and keeps tests clean and maintainable. Reading JSON in every test causes redundancy and slows tests. Hardcoding data reduces flexibility. Global variables can cause side effects and are discouraged.

Practice

1. What is the main benefit of reading test data from a JSON file in Selenium Python tests?

easy

A. It encrypts test data for security.

B. It makes tests run faster by avoiding web interactions.

C. It automatically generates test cases without writing code.

D. It keeps test code clean and makes data easy to update without changing code.

Solution

1. Step 1: Understand test data separation

   Reading test data from JSON separates data from test logic, making code cleaner.

2. Step 2: Recognize flexibility advantage

   Updating test data in JSON does not require changing test scripts, improving flexibility.

3. Final Answer:

   It keeps test code clean and makes data easy to update without changing code. -> Option D

4. Quick Check:

   Data separation = Clean code + Easy updates [OK]

Hint: Separate data from code for easy updates [OK]

Common Mistakes:

• Thinking JSON speeds up test execution
• Believing JSON auto-generates tests
• Confusing data storage with encryption

2. Which Python code snippet correctly reads a JSON file named data.json into a variable test_data?

easy

A. import json
test_data = json.load(open('data.json'))

B. test_data = open('data.json').read()

C. import json
test_data = json.loads('data.json')

D. test_data = json.read('data.json')

Solution

1. Step 1: Identify correct json module usage

   The json.load() function reads JSON from a file object, so open() must be passed to json.load().

2. Step 2: Check syntax correctness

   import json test_data = json.load(open('data.json')) correctly imports json and uses json.load(open('data.json')) to read the file.

3. Final Answer:

   import json\ntest_data = json.load(open('data.json')) -> Option A

4. Quick Check:

   json.load + open(file) = correct JSON read [OK]

Hint: Use json.load() with open() for files [OK]

Common Mistakes:

• Using json.loads() on filename string
• Forgetting to import json module
• Calling non-existent json.read() function

3. Given the JSON file user.json with content:

{"username": "testuser", "password": "pass123"}

and the code:

import json
with open('user.json') as f:
    data = json.load(f)
print(data['username'])

What will be the output?

medium

A. {'username': 'testuser', 'password': 'pass123'}

B. pass123

C. testuser

D. KeyError

Solution

1. Step 1: Load JSON data into dictionary

   The json.load(f) reads the JSON file and converts it into a Python dictionary with keys 'username' and 'password'.

2. Step 2: Access dictionary value by key

   data['username'] accesses the value 'testuser' from the dictionary.

3. Final Answer:

   testuser -> Option C

4. Quick Check:

   data['username'] = 'testuser' [OK]

Hint: Access JSON keys like dictionary keys [OK]

Common Mistakes:

• Printing the whole dictionary instead of key value
• Using wrong key causing KeyError
• Confusing json.load() with json.loads()

4. What is wrong with this code snippet that reads JSON test data?

import json
file = open('data.json')
data = json.load(file)
file.close()
print(data['email'])

Assuming data.json does not contain the key email.

medium

A. The code will raise a KeyError because 'email' key is missing.

B. The print statement syntax is incorrect.

C. The file is not closed properly.

D. json.load() cannot read from open file objects.

Solution

1. Step 1: Understand json.load() behavior

   json.load() correctly reads JSON from an open file object, so no error here.

2. Step 2: Identify missing key issue

   Accessing data['email'] when 'email' key is missing causes a KeyError at runtime.

3. Final Answer:

   The code will raise a KeyError because 'email' key is missing. -> Option A

4. Quick Check:

   Missing key access = KeyError [OK]

Hint: Check keys exist before accessing JSON data [OK]

Common Mistakes:

• Thinking json.load() fails on open files
• Ignoring possible missing keys in JSON
• Assuming file.close() is missing or wrong

5. You want to use JSON test data to fill a login form in Selenium Python. The JSON file login.json contains:

{"username": "user1", "password": "pass1"}

Which code snippet correctly reads the JSON and uses Selenium to fill the form fields with ids user and pass?

hard

A. import json
with open('login.json') as f:
data = json.load(f)
driver.find_element_by_name('user').send_keys(data['username'])
driver.find_element_by_name('pass').send_keys(data['password'])

B. import json
with open('login.json') as f:
data = json.load(f)
driver.find_element('id', 'user').send_keys(data['username'])
driver.find_element('id', 'pass').send_keys(data['password'])

C. import json
with open('login.json') as f:
data = json.loads(f)
driver.find_element_by_id('user').send_keys(data['username'])
driver.find_element_by_id('pass').send_keys(data['password'])

D. import json
with open('login.json') as f:
data = json.load(f)
driver.find_element('name', 'user').send_keys(data['username'])
driver.find_element('name', 'pass').send_keys(data['password'])

Solution

1. Step 1: Correctly read JSON file

   json.load(f) reads JSON from file object correctly; json.loads() expects a string, so import json with open('login.json') as f: data = json.loads(f) driver.find_element_by_id('user').send_keys(data['username']) driver.find_element_by_id('pass').send_keys(data['password']) is wrong.

2. Step 2: Use correct Selenium locator method

   driver.find_element('id', 'user') is the modern syntax to find element by id; find_element_by_id() is deprecated.

3. Step 3: Match locators with element ids

   The form fields have ids 'user' and 'pass', so locating by id is correct, not by name.

4. Final Answer:

   import json with open('login.json') as f: data = json.load(f) driver.find_element('id', 'user').send_keys(data['username']) driver.find_element('id', 'pass').send_keys(data['password']) -> Option B

5. Quick Check:

   json.load + find_element('id', ...) = correct usage [OK]

Hint: Use json.load() and find_element('id', ...) for form filling [OK]

Common Mistakes:

• Using json.loads() on file object
• Using deprecated find_element_by_id()
• Using wrong locator type (name instead of id)