A Complete Guide To End-to-end testing with Playwright

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End-to-end testing with Playwright

Playwright is a web automation framework. It provides a developer-friendly manner of designing and running tests. It was designed to allow competent and reliable cross-browser web automation. Developers can create robust Playwright tests using a single API thanks to its robust capabilities, which include auto-wait, web-first assertions, tracing, and the ability to span tests across tabs, sources, and users.

This guide to end-to-end testing with Playwright will give you all the information you need to make the most out of this framework.

What Exactly is Browser Automation?

We (should) always aim to automate processes as developers. We produce things more quickly, with less effort, at less money, with less reliance on human labour, and with more reliable outcomes than before.

We should automate browser-related tasks if we wish to build and perform UI tests for our web applications. The usage of input devices (keyboard, mouse, etc.) will need to be simulated, and we will need to check that the visual components are functioning and being presented properly. The automated use of a web browser is referred to as “browser automation.” The objective is to reach a level of productivity and speed that isn’t attainable if we rely just on human contact.

To automate browsers, there are a variety of tools at your disposal, each with its own functionality and implementation in a different computer language.

End-to-End Testing: What Is It?

Let’s first understand about end-to-end testing before moving on any further. E2E testing assesses if an application’s flow performs as anticipated from start to finish. End-to-end testing is carried out to identify system dependencies and confirm that data integrity is maintained across systems and system components.

Every programme is linked to and integrated with a number of other systems and databases. It goes without saying that this complicates the app’s workflow. This kind of testing verifies whether correct information is being sent between various system components and assesses whether app dependencies are functioning properly.

Playwright: What is it?

Playwright is a relatively new open-source cross-browser testing automation platform that Microsoft developed and maintains. Although it was an improvement over the Puppeteer tool, it did so fast. It was first developed to test Visual Studio Code, but it quickly became clear that it was a useful tool. It is intended to serve as a framework for testing across all of the most recent browsers and addressing the testing needs of today’s online applications.

Why Should I Use Playwright?

Playwright makes testing and automation efficient, powerful, and cross-browser compatible. These important distinctions are covered in this tutorial to assist you in selecting the best tool for your automated testing.

  • Acceptance of all browsers: 

  • Testing of WebKit across platforms: Test your app’s functionality in Apple Safari using WebKit binaries for Linux, Windows, and macOS using Playwright. local and CI testing
  • Test on WebKit, Firefox, and Chromium: All current browsers, including Apple Safari (with WebKit), Microsoft Edge (with Chromium), Google Chrome, and Mozilla Firefox, have complete API support from the Playwright.
  • Having no head at all:  For all platforms and browsers, Playwright provides headless (without browser UI) and headed (with browser UI) modes. Headless is quicker and more appropriate for CI/cloud runs whereas headless is ideal for debugging.
  • Test on mobile:  To test your responsive web applications in mobile web browsers, use device emulation.

 

  • Able to automate effectively

  • Network control is sturdy: In order to stub and simulate network requests, the Playwright implements context-wide network eavesdropping.
  • The ability to cover any circumstance: Support for native input events, out-of-process iframes, file downloads and uploads, and even dark mode.
  • Numerous pages, frames, and domains: The Playwright is an out-of-process automation driver that can automate situations including many pages and is not constrained by the scope of in-page JavaScript execution.
  • Web characteristics : Shadow-piercing selectors, geolocation, permissions, web workers, and other contemporary web APIs are supported by Playwright for web components.
  • Swift and trustworthy execution:
  • Automated without timeouts: Playwright receives browser signals like as network requests, page navigations, and page load events to do away with the requirement for sleep timeouts that lead to flakiness.
  • APIs that auto-wait: Playwright interactions automatically pause while waiting for available components. This enhances dependability and makes test writing easier.
  • Dependable element selectors: In order to choose components, the Playwright may depend on user-facing strings like text content and accessibility labels. These strings are more durable than selectors that are closely connected to the DOM architecture.
  • A quick isolation method using browser contexts: Use browser contexts to reuse a single browser instance across many separate execution environments.

Playwright:  A Modern, Open Source Approach to End-To-End Testing

Let’s have a deep look at the versatility of the Playwright framework.

  • Four different languages Can be used to write your test code:

Even though Node.js is Playwright’s preferred option, it also supports Java,.NET, and Python. Nobody wants to learn a new language simply to write some tests, so if your team utilises one of them, you’re in good hands.

  • On the Strength of the Chrome DevTools Protocol, Cross-Browser Tests

Playwright does not use the WebDriver protocol, in contrast to other options. To directly interface with Chromium browsers (Chrome/Edge), it makes use of the Chrome DevTools protocol. This strategy enables faster and more direct communication. Your testing will be more reliable and powerful.

Playwright, however, doesn’t stop with Chrome browsers. The project’s team recognised the need of cross-browser testing for an end-to-end testing solution. A smooth experience is also highly prioritised for Safari and Firefox, and even Android WebView support is in the pipeline.

 The only setting issue is testing your websites on Chrome, Edge, Firefox, and Safari. Additionally, this saves time and hassle!

  • Auto-Waiting Allows for Quick Tests

However, it goes beyond just automating several browsers. Your test suite will take hours to finish and become a nuisance if your tests are difficult to create because you have to include several “sleep” lines everywhere.

Playwright includes “auto-waiting” to reduce idly waiting. The concept is straightforward: Playwright does actionability checks for you rather to requiring you to determine if a button is clickable on your own.

A button click doesn’t need any sophisticated skills, right? There isn’t in Playwright, however. Additional convenience functionality is included in this innocent “click” call. The framework looks for a corresponding DOM element and waits for it to be:

– attached to the DOM

– able to receive events (not hidden or masked by other elements)

– visible

– stable (it is not moving or animating)

– enabled

All of these tests ensure that your target element is available for interaction when you need it and, more critically, that it gets clicked as soon as possible. Concerning DOM elements, don’t worry. Simply engage with them; stop using the wait statements and let the Playwright handle the rest.

All of Playwright’s interaction techniques have auto-waiting so that your test suite won’t have to run slowly. Your tests will be quicker to run and easy to write.But there’s more! Although Playwright may be used from the command line, it also includes helpful tools that make end-to-end testing simpler.

  • Scripts To Record With Codegen

Use Playwright’s test generator to get a head start on your first test. The Playwright Inspector and an interactive browser may both be launched using a single CLI command. Every action made in the browser window will be logged and shown in the inspector, which is the amusing part. These tools are ideal for setting up a basic setup if you want to construct a Playwright test that navigates someplace, clicks a button, and fills out a form.

Play back the created script, tweak your selectors, and you’re ready to go!

Congratulations! It probably didn’t take you more than a few minutes to construct your first end-to-end test.

  • While your scripts are running, debug them:

You will come across scenarios where you need to troubleshoot intricate scripts as your test suite expands. In these situations, Playwright offers a helpful debug perspective. The inspector in Playwright then launches a browser and, in a manner akin to your editor’s debugger, guides you through your test case. Additionally, it uses a little red circle to indicate the touched components so you can see what was clicked or filled in. This method is ideal for testing bug fixes while doing local development. However, how can you troubleshoot failing tests that are executed in CI or on a separate machine? There is a remedy for it as well!

  • Examine and fix earlier unsuccessful tests:

In a perfect world, your CI/CD pipeline would automatically execute your tests upon commit or deployment. Debugging failing tests from a separate environment, however, might be quite difficult.

Fortunately, you can activate a trace mode using the Playwright framework. Trace mode screenshots and preserves the current state of the webpage while recording all script activities.

When tests fail on your remote servers, utilise the Playwright tools that is given to load a produced “trace.zip” file and examine the test to see what went wrong. You’ll have access to method calls, a timeline, and screenshots—time it’s travel debugging at your disposal!

  • A Novel Approach to Synthetic Testing and Monitoring

These are just a few of the reasons why Playwright is now my testing framework of choice, and the team that created it works quickly to produce new versions each month. There is a highly active community Slack channel where you may talk to the maintainers or learn more about the Playwright framework. Do you still steer clear of end-to-end testing since they were formerly cumbersome and slow? We hope we were able to persuade you to give it another go. Because nothing is more satisfying than knowing that when creating and releasing software, nothing was broken.

  • Tools for Analysis, Debugging, and Creation

To make authoring end-to-end tests as simple as possible, Playwright offers extra commands and visual aids.

Guidelines & Techniques for Playwright

We discovered several important insights and advice when using Playwright, which can be helpful to you:

  • It will save you time to write tests by capturing your activities using the Codegen function.
  • Retires may be customised in the playwright configuration file. If a test fails, it is helpful. To get accurate results, you may retake the exam.
  • Investigating a test failure is possible using the Trace Viewer. This functionality offers realtime DOM snapshots, action explorer, test code, test execution screencasts, and more.
  • For execution and assertion during testing, use the timeout functionality.
  • Playwright’s built-in logger allows you to see the test execution and breakpoints.
  • You may rapidly recognise any element on the DOM by using the test data attributes during feature development to move the test through various items.

Advisable best practises

We discovered a few excellent practises when utilising Playwright for E2E testing of our marketplace applications, which may be useful in other situations.

  • Parallelism:
  • Playwright automatically runs test files, which allows numerous worker processes to execute at once.
  • The same worker process may be used to run tests in one file.
  • To lower the number of workers in the configuration file, it is possible to deactivate the test/file execution and execute it concurrently.
  • The execution time grows as the number of tests rises; tests that are executed in parallel are independent.
  • Isolation:
  • Run each test in a different browser to prevent any conflicts since each browser context is a unique incognito instance.
  • Each browser can simulate multi-page situations independently.
  • In the playwright configuration, you may set up several project criteria that correspond to the test environment, such as baseURL, devices, and browserName.
  • Speed of Performance:
  • The running of test results is sped up by parallel test execution, allocating worker processes, and isolation.
  • Regardless of the quantity of worker processes, factors like test data, global tear-down, and set-up have an impact on the execution speed.
  • Usage of Double Quotes: If you encounter numerous components on the same partial string, use double quotes.

Available Test Hooks in Playwright

Hooks from playwrights increase the effectiveness of testing remedies. The Playwright test hooks are listed below:

  • test.afterAll & test.beforeAll

The test.beforeAll hook creates test data that is shared throughout test execution, such as entries, content types, and a new stack. The test data is split or torn using the test.afterAll hook. This option aids in erasing any evidence of test-related data.

  • test.beforeEach&test.afterEach

This hook is used to organize and segment test data for distinct tests. Individual text execution and coinciding data, however, may differ. Users may configure the data to meet their requirements

Conclusion

With a strong emphasis on being an automation driver that integrates well with other components of your testing stack, Playwright is designed to be very versatile. It is adaptable, packed with features, and supported by a vibrant community and a reliable partner. It currently ranks among the top end-to-end testing solutions for online apps, in our opinion.

If we utilise a platform or have a grid to connect to, we can accomplish so since Playwright enables us to tie the browser to an existing session. 

You may test on an online browser farm of more than 50 browsers using LambdaTest’s cloud testing paltform for cross-browser testing on virtual machines. Chrome, Microsoft Edge, Chromium, Mozilla Firefox, Safari, and even Webkit are examples of this. Playwright automated testing may be run concurrently on any of these several browsers, greatly reducing the time required for test execution. You simply need to start and set up your capabilities after setting your browser to point to the currently running session.

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