Windmill vs Sinon.js comparison of testing frameworks
What are the differences between Windmill and Sinon.js?

Windmill

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

Sinon.js

https://sinonjs.org/
Programming language

Python

JavaScript

Category

UI Testing

Unit Testing

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

Standalone test stubs and mocks for JavaScript. Works with any unit testing framework.

Sinon.js is a great library when you want to unit test your code with supports spies, stubs, and mocks. The library has cross browser support and also can run on the server using Node.js.
xUnit
Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.

No

Yes

Compatible
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

Sinon.js is a good library for unit testing your front-end code and has cross browser support
Server-side
Allows testing the bahovior of a server-side code

No

Yes

Sinon.js can run on node.js to test back-end components and server-side behaviour
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

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

New BSD License; Modified 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

Yes

SinonJS is basically a library that we can use to create object mocks for unit testing
Grouping
Allows organizing tests in groups

N/A

Other
Other useful information about the testing framework