SimpleTest vs Playwright comparison of testing frameworks
What are the differences between SimpleTest and Playwright?

SimpleTest

https://github.com/simpletest/simpletest

Playwright

https://playwright.dev
Programming language

PHP

JavaScript

Category

Unit Testing, Web Testing

End-to-End Testing

General info

SimpleTest is a unit test and web test framework for PHP

It has JWebUnit style functionality and support for SSL, forms, frames, proxies and basic authentication

Test across all modern browsers. Use in your preferred language.

Single API to automate Chromium, Firefox and WebKit. Use the Playwright API in JavaScript & TypeScript, Python, .NET and, Java.
xUnit
Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.

No

Yes

While using xUnit is supported, it does not support running parallel tests. https://playwright.dev/dotnet/docs/test-runners/#xunit-support
Client-side
Allows testing code execution on the client, such as a web browser

Yes

With SimpleTest common but fiddly PHP tasks, such as logging into a site, can be tested easily

Yes

Test on Chromium, Firefox and WebKit. Playwright has full API coverage for all modern browsers, including Google Chrome and Microsoft Edge (with Chromium), Apple Safari (with WebKit) and Mozilla Firefox. Cross-platform WebKit testing. With Playwright, test how your app behaves in Apple Safari with WebKit builds for Windows, Linux and macOS. Test locally and on CI. Test for mobile. Use device emulation to test your responsive web apps in mobile web browsers. Headless and headed. Playwright supports headless (without browser UI) and headed (with browser UI) modes for all browsers and all platforms. Headed is great for debugging, and headless is faster and suited for CI/cloud executions.
Server-side
Allows testing the bahovior of a server-side code

Yes

Server-side behaviour can be tested by writing simple unit tests to test functionality and behaviour of single components.

Yes

While running tests inside browsers you may want to make calls to the HTTP API of your application. It may be helpful if you need to prepare server state before running a test or to check some postconditions on the server after performing some actions in the browser. All of that could be achieved via APIRequestContext methods.
Fixtures
Allows defining a fixed, specific states of data (fixtures) that are test-local. This ensures specific environment for a single test

Yes

It can import fixtures using a mixin like 'given()' method

Yes

Playwright Test is based on the concept of the test fixtures. Test fixtures are used to establish environment for each test, giving the test everything it needs and nothing else. Test fixtures are isolated between tests, which gives Playwright Test following benefits: Playwright Test runs tests in parallel by default, making your test suite much faster; Playwright Test can efficiently retry the flaky failures, instead of re-running the whole suite; You can group tests based on their meaning, instead of their common setup. Learn more at https://playwright.dev/docs/test-fixtures
Group fixtures
Allows defining a fixed, specific states of data for a group of tests (group-fixtures). This ensures specific environment for a given group of tests.

Yes

It allows grouping of fixtures

Yes

You can group tests based on their meaning, instead of their common setup.
Generators
Supports data generators for tests. Data generators generate input data for test. The test is then run for each input data produced in this way.

Yes

Simpletest has support for generators

Yes

Playwright comes with the ability to generate tests out of the box. Generate tests; Preserve authenticated state; Record using custom setup; Emulate devices; Emulate color scheme and viewport size; Emulate geolocation, language and timezone. Learn more at https://playwright.dev/docs/codegen/
Licence
Licence type governing the use and redistribution of the software

GNU Lesser General Public License v2.1

Apache License 2.0

Mocks
Mocks are objects that simulate the behavior of real objects. Using mocks allows testing some part of the code in isolation (with other parts mocked when needed)

Yes

It allows for one to build Mock objects.To create a mock version of a class we need to include the mock object library and run the generator. This will create a clone class which we use to create new instances(objects) in our test cases.

Yes

Playwright introduces context-wide network interception to stub and mock network requests. You can mock API endpoints via handling the network quests in your Playwright script. Learn more at https://playwright.dev/docs/network/#handle-requests
Grouping
Allows organizing tests in groups

Yes

There are several ways of grouping tests; one is to simply place multiple test cases into a single file, another is to mark any base test cases that should not be run as abstract, Simpletest gives you a couple of options

Yes

You can group tests to give them a logical name or to scope before/after hooks to the group.
Other
Other useful information about the testing framework

You can use the Playwright API in JavaScript & TypeScript, Python, .NET and, Java.