Multi-window interactions are more common than ever, enabling seamless workflows like authentication, file uploads, or social media integrations. However, automating these scenarios can be tricky due to the need to manage multiple browser windows or tabs simultaneously. In this blog post, we'll dive into how to tackle these challenges by automating a multi-window authentication flow using Playwright and Cypress.
The testing website is a simple yet functional demonstration of a user authentication flow involving multiple windows. The main page includes a button labeled "Authenticate" that, when clicked, opens a popup window. This popup simulates an authentication process where the user enters their username and submits it. Once submitted, the popup communicates the result back to the main window, updating the authentication status to confirm whether the user has been authenticated successfully.
Testing App Representation
The primary goal of this demo is to illustrate how interactions between the main page and a popup window can be automated. It mimics real-world scenarios like login authentication or third-party OAuth flows, where managing multiple browser windows is crucial for accurate test coverage.
Automating scenarios involving multiple windows can be challenging due to the need for seamless coordination between the main page and the popup. Using Playwright, we can efficiently handle this interaction and verify the authentication flow. Let's break down the code step by step to understand how this is achieved.
The first step in our automation script is to navigate to the main page of the testing website. This is done using Playwright's page.goto() method, which loads the specified URL. Here, we direct the Playwright browser to our testing website:
await page.goto("http://testing_website.com");
Once the page is loaded, the next task is to simulate a user clicking the "Authenticate" button. This action triggers the opening of the popup window. Since the popup is a new browser page, we use Playwright's context.waitForEvent("page") to wait for the popup to open. This ensures our script captures the newly created popup:
const [popup] = await Promise.all([
context.waitForEvent("page"),
page.locator("#authButton").click(), // Ensure the button click is awaited
]);
With the popup now open, the next task is to interact with its elements. First, we wait for the input field where the username is entered to appear. Using popup.locator() combined with waitFor(), we ensure the field is fully loaded before proceeding. Then, we fill it with the desired username:
const usernameField = popup.locator("#username");
await usernameField.waitFor();
const username = "TestUser";
await usernameField.fill(username);
After entering the username, the script simulates clicking the "Submit" button in the popup. This triggers the event that sends the username back to the main page and closes the popup:
const submitButton = popup.locator("#submit");
await submitButton.click();
Finally, the script verifies that the main page has been updated with the correct authentication status. We locate the #auth-status element and retrieve its text content to confirm that it matches the expected success message:
const authStatus = await page.locator("#auth-status").textContent();
expect(authStatus).toBe(`User ${username} successfully authenticated.`);
This Playwright script effectively handles the entire authentication process, including opening the popup, entering the username, submitting it, and verifying the results on the main page. Its modularity and reliance on synchronization points like waitForEvent and waitFor() ensure reliability, even in complex multi-window scenarios.
Cypress, unlike Playwright, operates within the same browser window and does not natively support handling multiple windows. However, it provides a way to stub and simulate popup interactions, making it possible to test multi-window scenarios effectively. Let's walk through how Cypress automates the authentication flow on the testing website.
First, we navigate to the main page of the testing website using cy.visit(). This ensures Cypress is ready to interact with the page:
cy.visit("http://testing_website.com");
Next, since Cypress does not directly interact with popup windows, we create a stub for window.open. This allows us to intercept the window.open call triggered by the "Authenticate" button and simulate the popup behavior. Using cy.stub(), we replace the window.open method with a mock implementation that Cypress can control:
cy.window().then((win) => {
cy.stub(win, "open")
.as("windowOpen")
.callsFake((url, target) => {
// Return a mock window object that Cypress can control
return {
document: {
write: cy.stub().as("documentWrite"),
},
close: cy.stub().as("windowClose"),
};
});
});
Once the stub is in place, we simulate the user clicking the "Authenticate" button. This triggers the window.open call, which is now intercepted by our stub. Cypress allows us to assert that the stub was called, confirming the popup would have opened:
cy.get("#authButton").click();
cy.get("@windowOpen").should("be.called");
To simulate interactions with the popup, we programmatically create mock elements representing the input field and the submit button. We set a value for the input field and dispatch a click event on the submit button. This mimics the behavior of entering a username and submitting the form:
cy.window().then((win) => {
const usernameInput = document.createElement("input");
usernameInput.id = "username";
usernameInput.value = "TestUser";
const submitButton = document.createElement("button");
submitButton.id = "submit";
const clickEvent = new Event("click");
submitButton.dispatchEvent(clickEvent);
win.document.getElementById(
"auth-status"
).textContent = `User ${usernameInput.value} successfully authenticated.`;
});
Finally, the script verifies the updated authentication status on the main page. Using cy.get(), we locate the #auth-status element and assert that its text matches the expected success message:
cy.get("#auth-status").should(
"have.text",
"User TestUser successfully authenticated."
);
Although Cypress does not directly interact with popup windows, this script demonstrates how to work around the limitation by stubbing and simulating the popup's functionality. By programmatically controlling the elements and their events, Cypress ensures the authentication flow is thoroughly tested while maintaining the simplicity and reliability it is known for.
Testing multi-window scenarios often highlights the strengths and limitations of different frameworks. Both Playwright and Cypress can handle such cases, but their approaches differ significantly due to their design philosophies and capabilities.
Playwright offers native support for handling multiple windows and tabs, making it a natural choice for testing scenarios involving popups. When a new window opens, Playwright detects it as a separate Page object, which can be directly interacted with. This allows for seamless automation of multi-window workflows without requiring complex workarounds.
In contrast, Cypress does not natively support interacting with multiple windows or tabs. It operates within a single browser context and prevents switching to new windows. Instead, Cypress encourages the use of workarounds, such as stubbing window.open to simulate popup behavior within the same browser context. While this approach ensures that Cypress tests remain deterministic, extra effort is required to simulate interactions that Playwright handles natively.
Playwright's robust multi-window support is ideal for testing applications where popups, modals, or new browser tabs are integral to user flows. Scenarios like authentication popups, third-party integrations, or workflows that span multiple browser contexts benefit from Playwright's ability to switch between windows seamlessly.
Cypress, while limited in this regard, excels in applications that require single-window testing. Its ability to stub and mock functionalities ensures reliability in tests where strict control over browser behavior is paramount. This makes it a good choice for testing SPAs (Single Page Applications) and for teams that prioritize speed and ease of setup over full multi-window capabilities.
Playwright's ability to directly interact with new windows results in highly reliable tests, as it avoids the need for mock implementations. Each window operates in its own browser context, reducing the risk of unintended side effects. Additionally, Playwright's multi-threaded architecture allows for faster execution when dealing with multiple windows or tabs.
Cypress, on the other hand, relies heavily on mocking and stubbing to achieve similar results. While this approach simplifies test execution within a single context, it can lead to lower fidelity when simulating real-world scenarios. However, Cypress compensates with its built-in time travel debugging and clear error messages, which are unmatched in aiding test troubleshooting.
Both tools have their strengths, but the choice depends on the specific needs of your testing project. For applications heavily reliant on multi-window workflows, Playwright's native capabilities make it the superior choice. For simpler applications and teams that value developer-friendly tooling, Cypress remains a strong contender.
Testing multi-window scenarios is a critical aspect of ensuring a seamless user experience in modern web applications. Playwright and Cypress each bring unique strengths to the table, with Playwright offering native support for multi-window interactions and Cypress providing robust control through clever workarounds. While Playwright shines in scenarios involving complex workflows across multiple browser contexts, Cypress remains a favorite for its simplicity and developer-friendly ecosystem.
Choosing the right tool depends on your application's requirements and your team's priorities. By understanding how these tools approach multi-window testing, you can better align your testing strategy with your project's needs, ensuring reliable and efficient automation for your workflows.
As always, complete code examples and the demo multi-window application are available on our GitHub page. See you soon.