Windmill vs Buster.JS comparison of testing frameworks
What are the differences between Windmill and Buster.JS?

Windmill

https://pypi.org/project/windmill/

Buster.JS

https://busterjs.readthedocs.io
Programming language

Python

JavaScript

Category

UI Testing

Unit Testing, Browser Automation

General info

Windmill is an Open Source Web UI testing framework for Python

Windmill is an Open Source AJAX Web UI testing framework that implements in-browser recording and playback, cross browser testing and test integration

Buster.JS is a JavaScript test framework for node and browsers.

Buster.JS is a new JavaScript testing framework. It does browser testing by automating test runs in actual browsers (think JsTestDriver), as well as Node.js testing. It has a bunch of great features.
xUnit
Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.

No

Yes

Buster.Js is a xUnit style Test Framework
Client-side
Allows testing code execution on the client, such as a web browser

Yes

Its main function is testing of front-end components and functionality

Yes

It does browser testing with browser automation, QUnit style static HTML page testing, testing in headless browsers and more front-end components and functionality
Server-side
Allows testing the bahovior of a server-side code

No

Yes

It is a Node.js testing toolkit as well which means it can test back-end behaviour and functionality as well as run in a server environment
Fixtures
Allows defining a fixed, specific states of data (fixtures) that are test-local. This ensures specific environment for a single test

N/A

N/A

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.

N/A

N/A

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

By using third party libraries

Licence
Licence type governing the use and redistribution of the software

Apache License 2.0

BSD License

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)

N/A

Buster.JS ships with Sinon.JS. every test in a test case has a sandbox associated with it, making it easy to mock and stub
Grouping
Allows organizing tests in groups

N/A

Other
Other useful information about the testing framework