28. Data-Driven Testing with @pytest.mark.parametrize

Parameterized Testing in pytest

import pytest
@pytest.mark.parametrize("username,password,expected_error", [
    ("invalid_user", "Secret123", "User not found"),
    ("admin@targetqa.com", "wrong_pass", "Invalid password"),
    ("", "Secret123", "Username required"),
])
def test_login_validation_errors(page, username, password, expected_error):
    page.goto("https://targetqa.com/login")
    page.get_by_label("Username").fill(username)
    page.get_by_label("Password").fill(password)
    page.get_by_role("button", name="Log In").click()
    expect(page.locator(".error-banner")).to_contain_text(expected_error)