PHPUnit vs Chai comparison of testing frameworks
What are the differences between PHPUnit and Chai?

PHPUnit

https://phpunit.de/

Chai

https://www.chaijs.com
Programming language

PHP

JavaScript

Category

Unit Testing

Unit Testing

General info

PHPUnit is a unit testing framework for the PHP programming language

PHPUnit is a programmer-oriented testing framework and is an instance of the xUnit architecture for unit testing frameworks.

Chai is a BDD / TDD assertion library for Node.js and the browser that can be paired with any JavaScript testing framework.

Chai is an assertion library, similar to Node's built-in assert and makes testing easier by giving you many assertions you can run against your code. It also includes a robust Plugin architecture for extending Chai's assertions and interfaces.
xUnit
Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.

Yes

It's an instance of the xUnit architecture for unit testing frameworks

N/A

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

Yes

It can perform Unit tests and can test various front-end components and behaviours

Yes

Chai can be used in a browser environment to test front-end components and functionality
Server-side
Allows testing the bahovior of a server-side code

Yes

By performing unit tests on singular back-end components

Yes

Chai is used in a Node.JS environment to test server behaviour and functionality
Fixtures
Allows defining a fixed, specific states of data (fixtures) that are test-local. This ensures specific environment for a single test

Yes

By use of a setup code. The setup code consists of two Important template functions, the 'setUp()' function (called to create the objects to be tested) and 'tearDown()' function (called to cleanup the objects which you tested)

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.

Yes

It does support group fixtures

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.

N/A

Yes

By using chai-spec-generator plugin which will generate chai test specs from a JavaScript object
Licence
Licence type governing the use and redistribution of the software

Creative Commons Attribution 3.0 Unported License

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)

Yes

One of its main features is that PHPUnit comes with out of the box support for Mock objects

Yes

By using by using a third party library like chai-jest-mocks which is a chai plugin that adds assertions for jest mock functions. You can also use sinon.js
Grouping
Allows organizing tests in groups

Yes

It allows grouping of tests and by using the @group annotation one can tag a test to belong to one or more groups

N/A

Other
Other useful information about the testing framework