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

NUnit

https://nunit.org/

Chai

https://www.chaijs.com
Programming language

.NET

JavaScript

Category

Unit Testing

Unit Testing

General info

NUnit is an open-source unit testing framework for Microsoft .NET.

NUnit was Initially ported from JUnit. Tests can be run from a console runner, within Visual Studio through a Test Adapter or through 3rd party runners. Tests can be run in parallel and has Strong support for data driven tests. Unit supports multiple platforms including .NET Core, Xamarin Mobile, Compact Framework and Silverlight.

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

Nunit is one of many programs in the xUnit family

N/A

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

Yes

You can test front-end components with NUnit since it is a Unit testing framework the application is isolated into diverse modules which are tested independently

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

You can test back-end components with NUnit, it is a Unit testing framework hence the application is isolated into diverse modules which are tested independently

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

NUnit contains the fixture methods SetUp to initialize your test environment and TearDown method to destroy a test environment

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

Group fixtures are available in NUnit

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

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

You can create mock objects using the third party library moq

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

You can group tests into suites with NUnit

N/A

Other
Other useful information about the testing framework