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

	Chai https://www.chaijs.com	Mocha https://mochajs.org
Programming language	JavaScript	JavaScript
Category	Unit Testing	Unit Testing, Intergration Testing, End-to-End Testing
General info	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.	Mocha is a widely used JavaScript test framework for Node.js Mocha is a simple, flexible and the one of the widely adopted JS test framework. Mocha usually runs tests serially which enables the accurate reporting. Also it's useful for asynchronous testing, and provides various king of test reports. Spec is default test reporter for mocha, there are many test reports like Nyan, Dot matrix, Tap, Landing strip, List and Progress. Mocha is being used with many other test frameworks like Selenium WebDriver, Webdriver.io, wd and Cypress
xUnit Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.	N/A	Yes It has an XUnit reporter available which outputs an XUnit-compatible XML document, often applicable in CI servers.
Client-side Allows testing code execution on the client, such as a web browser	Yes Chai can be used in a browser environment to test front-end components and functionality	Yes Mocha Runs in the browser and is used widely to test front-end components and functionality. It can test various DOM elements, front-end functions and so on.
Server-side Allows testing the bahovior of a server-side code	Yes Chai is used in a Node.JS environment to test server behaviour and functionality	Yes Mocha provides convenient ways of testing the Node server.It works well with Chai (an assertion library) where it provides the environment for writing server-side tests while we write the tests with Chai
Fixtures Allows defining a fixed, specific states of data (fixtures) that are test-local. This ensures specific environment for a single test	N/A	Mocha provides the hooks before(), after(), beforeEach(), and afterEach() to set up preconditions and clean up after your tests
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 Mocha allows grouping of 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.	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	MIT 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 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	Provides Mocking capabilities through third party libraries like sinon.js, simple-mock and nock
Grouping Allows organizing tests in groups	N/A	Yes Grouping is supported and is accomplished by the using a nested 'describe()'
Other Other useful information about the testing framework