Playwright Tutorial #5 - Automate First Test Case in Playwright

Summary

In this Playwright tutorial, the presenter walks viewers through writing their first test case from scratch. It covers essential concepts like importing dependencies, defining test functions using async/await, and managing asynchronous execution. The tutorial demonstrates how to launch a page, validate elements, and run tests in different browsers, with a focus on simplicity and efficiency. The presenter emphasizes how Playwright automates tasks more easily than traditional tools like Selenium, offering built-in functionalities to streamline testing and reduce maintenance efforts.

Takeaways

• 😀 Playwright is a powerful testing framework that helps automate browser interactions for testing web applications.
• 😀 When setting up a Playwright project, dependencies are installed, and a basic project structure is automatically created, including a sample test file.
• 😀 The key imports in Playwright tests are `test` and `expect`, which are used to define tests and validate outcomes respectively.
• 😀 Playwright tests in JavaScript use the `const` keyword to import dependencies, similar to how imports work in other languages like Java.
• 😀 Playwright is built on Node.js, meaning asynchronous programming is required. The `async` and `await` keywords ensure that test steps are executed sequentially.
• 😀 In Playwright, each test begins with the `test()` function, followed by a description (e.g., 'launch application') and a callback function with test steps.
• 😀 Tests in Playwright are asynchronous by nature, so using `await` ensures that each test step completes before moving on to the next one, preventing race conditions.
• 😀 The `expect` function in Playwright is used to assert that the actual value matches the expected value, like checking the title of the web page.
• 😀 Playwright supports running tests in various modes, including headless (no browser UI) and headed (with browser UI). The `npx playwright test` command runs tests, and appending `--headed` runs them with the browser UI visible.
• 😀 Playwright provides built-in reporting functionality, allowing users to view execution reports in HTML format for detailed insights into test results.
• 😀 Playwright simplifies test automation by providing everything in-built, reducing the need to manually create or maintain complex frameworks like in Selenium with Java.

Q & A

What is the purpose of the first test case in the Playwright tutorial?

The first test case demonstrates how to write a simple test using Playwright in JavaScript. It includes the basic setup, writing a test that launches a page, and performing an assertion to check the page's title.

What dependencies are imported to write tests in Playwright using JavaScript?

The `test` and `expect` functions are imported from Playwright. These are used to define the test case and assert expected results, respectively.

Why is the `async` keyword required when writing Playwright tests?

The `async` keyword is required because Playwright is built on JavaScript and Node.js, which are asynchronous by nature. This ensures that test steps execute in a synchronous fashion, waiting for each action to complete before moving to the next.

What does the `await` keyword do in Playwright tests?

The `await` keyword is used alongside `async` to ensure that an asynchronous operation (like navigating to a page or clicking a button) completes before proceeding to the next step. It is necessary to maintain proper sequence in the test.

How is the page title validated in the test case?

The page title is validated using the `expect` function. The title of the page is retrieved using `page.title()`, and it is compared to the expected value using `expect().toBe()`, ensuring that the actual title matches the expected title.

What is the difference between synchronous and asynchronous execution in Playwright?

In synchronous execution, each test step waits for the previous step to complete before starting. In asynchronous execution, multiple steps can be triggered at the same time, but Playwright ensures that actions like page loading are completed properly using `await`.

How do you execute a specific test case in Playwright?

To execute a specific test case, you use the command `npx playwright test <filename>`, where `<filename>` is the name of the test file you want to run. For example, `npx playwright test firstTest.spec.js` runs the `firstTest.spec.js` file.

What is the difference between running tests in 'headless' and 'headed' modes?

In 'headless' mode, the tests run without opening a visible browser window, which is faster and typically used in CI/CD environments. In 'headed' mode, the browser window is visible, allowing you to watch the test execution in real-time.

What does the `npx playwright show-report` command do?

The `npx playwright show-report` command generates and displays an HTML report of the test execution. It includes details about the execution in various browsers (Chromium, Firefox, WebKit) and the steps taken during the test.

How does Playwright handle asynchronous behavior in tests?

Playwright handles asynchronous behavior by using `async` and `await`. Each action in the test, such as navigating to a page or checking for an element, is executed asynchronously, but using `await` ensures the correct order of execution.