Playwright: Tackling the Logout and Login Challenge Within a Single Test
End-to-end testing is a powerful tool for ensuring your web application functions flawlessly across various user scenarios. But what happens when your test requires a user to logout and login as a different user within the same test execution? Playwright, a popular automation library, often encounters a challenge when attempting to manage these consecutive logins within a single test.
The Scenario: A Logout and Login Within a Single Test
Imagine a scenario where you want to verify that a user can successfully log out of an application, and then a new user can successfully log in with different credentials.
Let's assume you have a basic Playwright test like this:
const { test, expect } = require('@playwright/test');
test('Logout and login as a new user', async ({ page }) => {
// Login with user1 credentials
await page.goto('https://www.example.com/login');
await page.fill('input[name="username"]', 'user1');
await page.fill('input[name="password"]', 'password1');
await page.click('button[type="submit"]');
// Logout
await page.click('a[href="/logout"]');
// Login with user2 credentials
await page.goto('https://www.example.com/login');
await page.fill('input[name="username"]', 'user2');
await page.fill('input[name="password"]', 'password2');
await page.click('button[type="submit"]');
// Expect to be logged in as user2
expect(await page.$('h1')).toHaveText('Welcome, user2!');
});
The problem arises when Playwright struggles to properly clear the browser's cache and cookies after the logout, resulting in the second login attempt inadvertently using leftover authentication information from the first user. This can lead to unexpected test failures.
The Solution: Strategies for Handling Logout and Login
Here are a couple of effective strategies to address this challenge:
- Context Isolation: The most reliable approach is to use separate browser contexts for each login. Playwright allows you to create isolated contexts that operate independently, eliminating the issue of persistent cookies or cached data.
const { test, expect } = require('@playwright/test');
test('Logout and login as a new user', async ({ browser }) => {
const context1 = await browser.newContext(); // Create a new context
const page1 = await context1.newPage();
// Login with user1 credentials using context1 and page1
// ...
// Logout using context1 and page1
// ...
const context2 = await browser.newContext(); // Create another new context
const page2 = await context2.newPage();
// Login with user2 credentials using context2 and page2
// ...
// Expect to be logged in as user2 using page2
// ...
});
- Explicit Cookie Clearing: Alternatively, you can clear the browser's cookies manually using Playwright's API. This method might not be as robust as context isolation but can be a viable option for simpler scenarios.
const { test, expect } = require('@playwright/test');
test('Logout and login as a new user', async ({ page }) => {
// Login with user1 credentials
// ...
// Logout
// ...
// Clear cookies
await page.context().clearCookies();
// Login with user2 credentials
// ...
});
Optimizing Your Test for Readability and Maintainability
When dealing with multiple user logins within a test, consider using helper functions to streamline the process and enhance readability. These functions can encapsulate common login or logout actions, reducing code duplication and improving maintainability.
const { test, expect } = require('@playwright/test');
async function login(page, username, password) {
await page.goto('https://www.example.com/login');
await page.fill('input[name="username"]', username);
await page.fill('input[name="password"]', password);
await page.click('button[type="submit"]');
}
test('Logout and login as a new user', async ({ browser }) => {
const context1 = await browser.newContext();
const page1 = await context1.newPage();
await login(page1, 'user1', 'password1');
// Logout using page1
// ...
const context2 = await browser.newContext();
const page2 = await context2.newPage();
await login(page2, 'user2', 'password2');
// Expect to be logged in as user2 using page2
// ...
});
Conclusion
Navigating logout and login within a single Playwright test requires careful consideration and proper implementation. By embracing context isolation or employing explicit cookie clearing, you can ensure the integrity of your testing process and achieve reliable test results. Utilizing helper functions can further enhance your test's readability and maintainability. Remember to prioritize a clear and structured approach, enabling you to create robust and efficient end-to-end tests that capture the complete user experience.
