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

Chai

https://www.chaijs.com

AVA

https://github.com/avajs/ava
Programming language

JavaScript

JavaScript

Category

Unit Testing

Unit Testing, Intergration 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.

Futuristic, new, fast and concurrent JavaScript test runner with simple test syntax

AVA is a test runner for Node.js with a concise API, detailed error output. JS is a single-threaded but Node.JS is a parallel due to it's async behaviour. Ava leverages that and it can run tests concurrently
xUnit
Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.

N/A

No

However Ava supports the TAP format which allows us to use the tap-xunit reporter to produce xUnit (JUnit) XML
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

You can write tests for the DOM with Ava, testing front-end components is easy with Ava
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

Ava utilizes the async I/O nature of Node and runs concurrent tests on NodeJs applications' back-endsA node server can have its endpoints tested with Ava
Fixtures
Allows defining a fixed, specific states of data (fixtures) that are test-local. This ensures specific environment for a single test

N/A

Yes

Using Ava's ava-fixture library it supports fixtures
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

Yes

Ava has support 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.

Yes

By using chai-spec-generator plugin which will generate chai test specs from a JavaScript object

N/A

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

AVA has no mocking built in, to mock functions you can use third party libraries like Sinon.js.
Grouping
Allows organizing tests in groups

N/A

No

There is no support for grouping tests
Other
Other useful information about the testing framework