Kotest vs Unit.js comparison of testing frameworks
What are the differences between Kotest and Unit.js?

Kotest

https://github.com/kotest/kotest

Unit.js

https://unitjs.com/
Programming language

Kotlin

JavaScript

Category

Unit Testing

Unit Testing, End-to-End Testing

General info

kotest is a powerful, elegant and flexible test framework for Kotlin, formerly known as kotlintest

Kotest has excellent support for data driven testing or table driven testing where it has the ability to quickly rerun the same test over and over with a predefined set of inputs and expected values

An assertion library for JavaScript (similar to chai.js)

It works with any test runner and unit testing framework like Mocha, Jasmine, Karma, protractor (E2E test framework for Angular apps) and QUnit.
xUnit
Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.

No

Client-side
Allows testing code execution on the client, such as a web browser

Yes

You can test front-end components with kotest

Yes

Unit.js runs in the browser to test front-end components
Server-side
Allows testing the bahovior of a server-side code

Yes

Yes, you can test back-end components with kotest

Yes

Unit.js runs in nodejs to test 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

Yes

kotest contains fixtures, that is the setup / teardown functions

Yes

Unit.js provides Test fixtures for running testsThis is one of its features
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

kotest has group fixtures available

Yes

With Unit.js you can group your fixtures
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.

N/A

Licence
Licence type governing the use and redistribution of the software

Apache License 2.0

GNU

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

You can use a third party library like mockk to create mocks

N/A

Grouping
Allows organizing tests in groups

Yes

You can create test suites with kotest

N/A

Other
Other useful information about the testing framework