In the fast-paced world of software development, automated web testing is a necessity for building robust products. Choosing the right automation tool is crucial, and Playwright, a cutting-edge framework from Microsoft, has swiftly become a formidable contender in the web automation landscape.
Born from the creators of Puppeteer, Playwright is an open-source Node.js-based framework with key features that set it apart. Despite its 2019 debut, Playwright has rapidly evolved into a mature and widely adopted tool, solidifying its position in the test automation space next to Selenium and Cypress.
Resilient test runs
The primary cause of flaky tests in automation is due to the speed of the test automation tools. The tool tends to go faster than the browser is capable of loading and rendering the pages. This often results in synchronization issues, causing tests to fail. Testers need to implement their own set of artificial waiting mechanisms. These workarounds can be time-consuming and error prone. Playwright addresses this issue head-on with its robust features:
Playwright eliminates synchronization issues with its advanced auto-wait feature. Unlike Selenium, Playwright proactively monitors element readiness, reducing the need for manual waiting mechanisms and ensuring more reliable tests.
Playwright enhances auto-wait with introspection events, providing detailed insights into element states. This intelligence contributes to the reliability and stability of Playwright tests, minimizing synchronization issues.
Playwright offers web-first assertions designed for dynamic web applications. These assertions, powered by the expect library, continuously monitor application states, providing stability and accuracy in testing dynamic environments.
While Playwright’s auto-wait and web-first assertions effectively address test flakiness, it also offers tracing as an additional tool for debugging and eliminating flaky tests. By configuring a test retry strategy and capturing detailed execution traces, automation testers have all information needed to debug and eliminate remaining flaky tests.
Playwright’s communication with browser drivers is faster than traditional tools, thanks to the use of the DevTools Protocol and an event-driven architecture. Direct communication enhances efficiency, speeding up command execution and response retrieval (see speed comparison).
Headless and headful
Playwright supports both headless and headful modes, offering flexibility in testing approaches. This allows for interactive and immersive testing experiences, catering to various testing scenarios.
Versatile browser capabilities
Playwright goes beyond basic interactions, enabling the creation of test scenarios across multiple tabs, origins, and users. It supports complex actions like hovering elements, making it ideal for testing multi-user scenarios or conducting parallel testing across multiple browsers simultaneously.
For each test, Playwright creates a browser context, which is equivalent to a new browser profile. Creating a browser context only takes a matter of milliseconds, and the result is full test isolation with no overhead. This isolation ensures that test executions do not interfere with each other. Additionally, browser contexts enable the simulation of private sessions and multi-page scenarios. Next to this we also have
- Isolated browser context: these provide an even higher level of isolation, ensuring that tests running within the same browser instance do not affect each other.
- Concurrency groups: they allow developers to group tests based on their resource requirements or dependency relationships. Tests within the same concurrency group are executed in a controlled manner.
Playwright comes with a comprehensive set of tools that enhance the overall testing experience.
- Test Generator / codegen: allows automation testers ro record user interactions and generates test scripts in various programming languages. It also enables emulation of various device and browser configurations, including viewport sizes, geolocation settings, language preferences, and timezones.
- Playwright Inspector: a graphical user interface (GUI) tool that facilitates script authoring and debugging your test scripts.
- Trace Viewer: a GUI tool that displays detailed traces of test executions. This comprehensive information helps developers pinpoint the exact moments where tests fail, enabling targeted debugging and issue resolution.
Playwright is a powerful tool with many features. However, there are a few limitations to consider:
- Community: Playwright’s community is still growing, but it’s getting more established over the years.
- Learning Curve: Playwright’s API and features can be more complex compared to other tools, requiring a steeper learning curve for new developers. But this has been improved with better documentation and tutorials.
- Internet Explorer 11 Support: Playwright does not currently support Internet Explorer 11, which may restrict its use for some legacy web applications.
While Playwright has made significant strides in recent years addressing several of its initial limitations, making it a more mature and versatile web automation tool. With each release introducing new features and enhancements. Setting them on the right track to becoming a top contender in the web automation landscape.
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