Reading test data from JSON in Selenium Python - Framework Patterns

Framework Mode - Reading test data from JSON

Folder Structure

selenium-python-project/
├── tests/
│   ├── test_login.py
│   └── test_checkout.py
├── pages/
│   ├── login_page.py
│   └── checkout_page.py
├── data/
│   └── test_data.json
├── utils/
│   └── json_reader.py
├── config/
│   └── config.yaml
├── drivers/
│   └── chromedriver.exe
└── requirements.txt

This structure keeps test data in the data/ folder as JSON files. Utility code to read JSON is in utils/json_reader.py. Tests use this data to run with different inputs.

Test Framework Layers

• Driver Layer: Manages browser drivers (e.g., ChromeDriver) to control browsers.
• Page Objects: Classes representing web pages with methods to interact with page elements.
• Tests: Test scripts that use page objects and test data to perform checks.
• Utilities: Helper functions like JSON readers to load test data from files.
• Configuration: Settings for environments, browsers, and credentials stored in config files.

Configuration Patterns

• Environment Config: Use config/config.yaml to store URLs, browser types, and credentials.
• Test Data: Store test inputs in JSON files inside data/ folder.
• Loading Data: Use a utility function in utils/json_reader.py to read JSON and return Python dictionaries.
• Parameterization: Tests read data from JSON and run multiple times with different inputs.

Test Reporting and CI/CD Integration

• Use pytest with plugins like pytest-html to generate readable HTML reports.
• Integrate tests in CI/CD pipelines (e.g., GitHub Actions, Jenkins) to run tests automatically on code changes.
• Reports include which test data inputs passed or failed, helping track data-driven test results.

Best Practices

• Separate Test Data: Keep test data outside test code for easy updates without code changes.
• Reusable JSON Reader: Create a single utility function to read JSON files to avoid duplication.
• Clear Naming: Name JSON keys clearly to match test input fields for easy mapping.
• Parameterize Tests: Use test frameworks' parameterization features to run tests with multiple data sets.
• Keep Data Small: Keep JSON test data focused and small for fast test runs and easy maintenance.

Self Check

Where in this folder structure would you add a new JSON file for test data related to user registration?

Key Result

Store test data as JSON files in a dedicated data folder and load them via utility functions for data-driven Selenium tests in Python.

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)