Test login with multiple user credentials using parametrized fixture

Preconditions (2)

Step 1: Open the login page.

Step 2: Enter the username from the test data into the username field.

Step 3: Enter the password from the test data into the password field.

Step 4: Click the login button.

Step 5: Verify that the user is redirected to the dashboard page with URL containing '/dashboard'.

Step 6: Logout to prepare for the next test data input.

✅ Expected Result: For each set of credentials, the user successfully logs in and is redirected to the dashboard page.

Automation Requirements - pytest

Assertions Needed:

Verify the current URL contains '/dashboard' after login.

Verify the login button is clickable before clicking.

Verify logout button is present after login.

Best Practices:

Use pytest parametrized fixtures to supply multiple sets of credentials.

Use explicit waits to ensure elements are interactable.

Keep test functions simple and readable.

Use fixture scope appropriately.

Automated Solution

PyTest

import pytest
from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC

@pytest.fixture(params=[
    {"username": "user1@example.com", "password": "Pass123!"},
    {"username": "user2@example.com", "password": "Pass456!"},
    {"username": "user3@example.com", "password": "Pass789!"}
])
def credentials(request):
    return request.param

@pytest.fixture
def driver():
    driver = webdriver.Chrome()
    driver.implicitly_wait(5)
    yield driver
    driver.quit()

def test_login_with_parametrized_credentials(driver, credentials):
    driver.get("http://example.com/login")

    # Wait for username field and enter username
    username_field = WebDriverWait(driver, 10).until(
        EC.element_to_be_clickable((By.ID, "username"))
    )
    username_field.clear()
    username_field.send_keys(credentials["username"])

    # Wait for password field and enter password
    password_field = WebDriverWait(driver, 10).until(
        EC.element_to_be_clickable((By.ID, "password"))
    )
    password_field.clear()
    password_field.send_keys(credentials["password"])

    # Wait for login button and click
    login_button = WebDriverWait(driver, 10).until(
        EC.element_to_be_clickable((By.ID, "loginBtn"))
    )
    login_button.click()

    # Verify URL contains '/dashboard'
    WebDriverWait(driver, 10).until(
        EC.url_contains("/dashboard")
    )
    assert "/dashboard" in driver.current_url

    # Verify logout button is present
    logout_button = WebDriverWait(driver, 10).until(
        EC.presence_of_element_located((By.ID, "logoutBtn"))
    )
    assert logout_button.is_displayed()

    # Logout to reset state
    logout_button.click()

This test uses a pytest parametrized fixture named credentials to supply three different sets of user login data.

The driver fixture sets up the Selenium WebDriver and ensures it quits after the test.

The test function test_login_with_parametrized_credentials uses these fixtures. It opens the login page, waits explicitly for each element to be clickable before interacting, and enters the username and password from the current parameter set.

After clicking login, it waits until the URL contains '/dashboard' to confirm successful login, then asserts this condition.

It also checks that the logout button is visible, confirming the user is logged in.

Finally, it clicks logout to reset the state for the next test iteration.

This approach keeps tests clean, readable, and reliable by using explicit waits and parametrization.

Common Mistakes - 3 Pitfalls

Hardcoding credentials inside the test function instead of using parametrized fixtures

Not using explicit waits before interacting with elements

Not resetting the application state after each test iteration

Bonus Challenge

Now add data-driven testing with 3 different sets of invalid credentials and verify login failure message.

Show Hint