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

Unit.js

https://unitjs.com/

Behat

https://docs.behat.org/en/latest/
Programming language

JavaScript

PHP

Category

Unit Testing, End-to-End Testing

Functional/Acceptance Testing

General info

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.

Behat is an open source Behavior-Driven Development framework for PHP.

Behat uses the StoryBDD subtype of behaviour-driven development (the other subtype is SpecBDD); This means the tests we write with Behat look rather like stories than code. It is inspired by Ruby's Cucumber
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

Unit.js runs in the browser to test front-end components

Yes

To enable Behat to test a website, you need to add Mink and a browser emulator (selenium maybe, though slow) to the mix. Mink methods are the connector between Behat and an extensive list of available drivers, and they provide a consistent testing API.
Server-side
Allows testing the bahovior of a server-side code

Yes

Unit.js runs in nodejs to test server-side behaviour

Yes

Behat can be used for Data Integrity Testing to verify that database operations are functioning properly
Fixtures
Allows defining a fixed, specific states of data (fixtures) that are test-local. This ensures specific environment for a single test

Yes

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

Yes

One can use the 'Doctrinefixturesbundle' to create the required fixture loaders and load them in our Behat scenarios when required, using the 'BeforeScenario' hook.
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

With Unit.js you can group your fixtures

Yes

Behat allows for group 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.

By use of third party libraries like moodle-behat-generators
Licence
Licence type governing the use and redistribution of the software

GNU

MIT 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

By using third party libraries like Mock and Prophecy
Grouping
Allows organizing tests in groups

N/A

Yes

You can use tags to group features and scenarios together, independent of your file and directory structure
Other
Other useful information about the testing framework