Parametrize with indirect fixtures in PyTest - Build an Automation Script

Test login functionality with multiple user roles using indirect fixtures

Preconditions (3)

Step 1: Use pytest.mark.parametrize to pass different user roles to the 'user' fixture indirectly

Step 2: For each user role, call the login function with credentials from the fixture

Step 3: Verify that login returns success for valid users

✅ Expected Result: The test runs for each user role, login succeeds, and assertions pass for all cases

Automation Requirements - pytest

Assertions Needed:

Assert login function returns True for each user role

Best Practices:

Use pytest.mark.parametrize with indirect=True to pass parameters to fixtures

Keep test functions simple and focused

Use fixtures to manage setup and teardown

Automated Solution

PyTest

import pytest

# Simulated login function

def login(username, password):
    valid_users = {"admin": "adminpass", "guest": "guestpass", "user": "userpass"}
    return valid_users.get(username) == password

# Fixture that receives user role indirectly
@pytest.fixture
def user(request):
    role = request.param
    credentials = {
        "admin": ("admin", "adminpass"),
        "guest": ("guest", "guestpass"),
        "user": ("user", "userpass")
    }
    return credentials[role]

# Test function using indirect parametrize
@pytest.mark.parametrize("user", ["admin", "guest", "user"], indirect=True)
def test_login(user):
    username, password = user
    assert login(username, password) is True

This code defines a login function that checks if the username and password match known valid users.

The user fixture uses request.param to receive the user role indirectly from the test parameter. It returns the corresponding credentials tuple.

The test test_login uses pytest.mark.parametrize with indirect=True to pass the user roles to the user fixture. For each role, it gets credentials and asserts that login succeeds.

This approach keeps test data separate from setup logic and makes tests clear and reusable.

Common Mistakes - 3 Pitfalls

Not using indirect=true in parametrize when passing parameters to fixtures

Hardcoding credentials inside the test instead of using fixtures

Using mutable default arguments in fixtures

Bonus Challenge

Now add data-driven testing with 3 different sets of invalid credentials to verify login fails

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