To ensure that your website works as you intend it to, it is essential to test every component. Playwright’s end-to-end testing capability makes it easy to do this. If you are comfortable with Python, you can use it in conjunction with the Playwright Testing framework to perform Python end-to-end testing on your site.
The Playwright testing framework has more straightforward and lighter than many other alternatives, such as Cypress or TestCafe. It also offers API Testing. It’s an excellent choice to do end-to-end testing.
This blog will try to understand end-to-end testing and why many of us want to use Playwright to execute our test. Let’s get started!
All You Should Know About End-to-End Testing
End-to-end testing validates every aspect of an application’s usage to ensure it functions as intended. It involves paying attention and expanding the testing coverage to find and fix bugs. Its ultimate goal is to help you create a bug-free website.
It’s a popular method for testing complex websites. It involves considering your website’s user story and then simulating your users’ behavior in various integration environments.
End-to-end testing is vital because you need to consider browser variability and operating system variations, as well as other factors that can affect the viability of an app. It involves a comprehensive test from the back (API testing) to the front.
Automated end-to-end testing can reduce testing costs, increase application integrity and help your product ship more quickly.
What Is Playwright?
Why Should You Use Playwright For Python End-to-End Testing?
The Playwright Framework provides many event inducers that allow you to interact with various client-side features of your site like a real user. It works with both synchronous as well as asynchronous requests. You can run your test sequentially or use the power of Python for concurrent execution using wait. It is useful for interfacing with websites that run tasks simultaneously.
Its API testing capabilities allow you to validate the requests and replies on your app’s endpoints.
The Playwright will isolate each test according to the browser used. Playwright defines each case as a browser context. This allows for the rapid creation of browser instances to reduce overhead.
Playwright’s versatility and Python’s acceptance make it easy to automate testing. Python is third in the most popular programming languages, according to the 2021 Developer Survey.
The popularity of the Playwright framework is high. There are over 2.3k+ forks and more than 46.8k+ stars on GitHub. What’s more? You also get fair mentions on Stack Overflow, which has a great community. You can always ask for help in resolving bugs in tests.
Playwright’s auto-wait feature is different from Selenium’s. It allows you to pause for DOM elements to load before proceeding with the test case. The default wait time is 30 seconds. However, you can increase this by using Playwright’s wait_for_timeout() function. Playwright will have a lower chance of false failure.
Playwright offers an inspector tool that you can use to generate selectors as you write your tests quickly. It reduces or eliminates the need to inspect your browser manually.
The code generator works in a “play-and-record” fashion. It can be used to create a DOM-based app and generate test scripts. This is useful if you aren’t familiar with programming, but it’s not customizable. This code is too long and complicated for complex websites, such as e-commerce and banking.
Easy Steps To Setup Playwright For Python End-to-End Testing
To use Playwright Python to automate testing, you must first install it. This Playwright Python tutorial assumes your machine is running Python 3.
Step 1: Install Python’s latest version. To download the most recent version of Python, visit the official Python website.
Python is not included in Windows OS by default. You will need to install it manually. During installation, ensure that the installer allows Python to be added to your system’s variable path. Otherwise, you will need to do it later manually.
To install Python on Windows:
- Open the installation file.
- At the bottom of the window, click the Add Python To Path box. Next, click Installation Now.
- The following menu will be used to initiate the installation.
Although most Linux distributions have Python pre-installed, Playwright may require you to upgrade to the latest version. Playwright works only with Python version 3.7 and later.
Step 2: Install Playwright and its WebKit.
Step 3: Create Project Folder. Next, you will need to create a project directory for automated testing. One can be created from the command line or through your graphic user interface.
In this Playwright Python tutorial, we’ll be using Visual Studio Code for Windows. You can also use the IDE that suits you best.
Working On Playwright Code Generator
Playwright’s code generator makes scanning the DOM easy without going to the inspection tab. It is limited in browser selection and does not allow for custom testing, but no-code-lovers can use it to generate test scripts automatically while interacting with UI.
There are two ways that the code generator works. It can be used to select the appropriate selectors for your website. You can also create a test case script using its record and play functionality.
Pros Of Playwright Code Generator:
- If you want to expand the use case, it will automatically generate code.
- It is useful for selecting test selectors for custom-built automated tests.
- Code can be generated for any Playwright-supported language.
Cons Of Playwright Code Generator:
- Generated code cannot be scaled and maintained.
- It is not recommended for testing complicated websites.
- Parallel tests cannot be executed since the code file only has one line of code.
- It is difficult to debug and read the generated code.
- It does not allow for the connection to a cloud grid.
- As you add more tests, the codebase gets messy.
- These test cases are repeated.
How To Implement Python End-to-End Testing With Playwright
You may want to inspect website elements before you begin testing. Move your cursor over an element and then right-click to inspect (for Chrome or any other browser).
Tip To generate the selectors, you can use the Playwright generator. It can be launched by using the playwright codegen command. Move your cursor over the elements to reuse the selectors generated in your test code. Codegen, as mentioned previously, is very useful in generating selectors because selectors are an integral component of any automation code.
The tests would be run using Playwright Python in parallel and in series. Our test scenario will use a real user story to show our end-to-end test. To learn more about parallel testing, please read this Playwright Python tutorial.
Our test will be run on the LambdaTest cloud grid. You’ll need your username and secret keys from the LambdaTest Builder Dashboard. Click the Access Key tab in the top-right.
A cloud-based testing platform like LambdaTest can drastically reduce the time it takes to run Playwright Python tests. It uses a browser farm that includes 50+ browsers and browser versions of Chrome and Mozilla Firefox.
These tests are performed using the LambdaTest e-commerce playground. These are the use cases for this Playwright Python tutorial:
Test Scenario – 1 (New User Registration)
- The user launches the LambdaTest registration page for the e-commerce playground.
- Complete the registration form.
- The user completes the registration form.
- For the first time, go to their dashboard.
Test Scenario 2 (Login and Buy Item)
- Logging in with the registered account is required.
- Your search for a product.
- Step 2: The user chooses the product they are looking for.
- Add the product to your cart
- The user confirms.
- Log out
Playwright Python Testing Structure:
To structure our test project, we will use the Page Object Model (POM design pattern) to structure our test project. Our code structure in this example separates the concerns into separate files for modularization. This allows us to scale our code later and eliminate complexities. The Page Object Model design pattern is known for its ease of use and maintainability. You might, for example, want to separate parallel test cases from one another.
Implementing Parallel Testing with Playwright Python
Cross-browser regression test on multiple browsers simultaneously helps you find issues quicker and allows you to get on with other work. For efficiency reasons, we will keep the same browser configurations used for parallel testing.
You can simulate a cloud grid with multiple servers where your test cases can be run simultaneously on different cloud host machines. This allows you to verify that your app is compatible with different integration environments.
Parallel testing is used in this example to iterate through the test cases using a capabilities array. For this section of the Playwright Python tutorial, we will run registration and login tests using two browser capabilities: Chrome and Microsoft Edge.
The Playwright testing framework offers simple methods to perform end-to-end testing. This article will demonstrate how Playwright Python can be used for parallel and single testing. For simplicity, we wrapped all of our test cases in the POM model.
We began by investigating the potential of Playwright’s code generator and how it could help us automatically create test cases code and selectors. This method was too complex and inflexible, so we developed a custom, end-to-end Playwright test that focuses on user registration and product purchases on the LambdaTest online marketplace.
We were able to create a parallel cross-browser test for the same test scenario. You’ve also learned how to create class methods to connect your tests with the LambdaTest Cloud Grid.