Cucumber vs Intern comparison of testing frameworks
What are the differences between Cucumber and Intern?

Cucumber

https://github.com/cucumber/cucumber-ruby

Intern

https://github.com/theintern/intern
Programming language

Ruby

JavaScript

Category

Acceptance Testing

Unit Testing, Functional Testing

General info

An automation tool for Behavior-Driven Development

The specifications are written in plain texts, which allows them to be easily understandable for all stakeholders. Cucumber Framework also supports languages beyond Ruby e.g. Java, JavaScript and Scala.

Intern is minimal test system for JavaScript designed to write and run consistent.

Intern is a complete test system for JavaScript designed to help you write and run consistent, high-quality test cases for your JavaScript libraries and applications. Using Intern we can write tests in JavaScript and TypeScript using any style like TDD, and BDD. Intern can run unit tests in most browsers that support ECMAScript
xUnit
Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.

No

No

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

Yes

You can test the front-end part like the GUI using cucumber and selenium, they integrate well to test your front-end.

Yes

Intern is a complete test system for JavaScript It Runs in the browser and can test any front-end component and functionality
Server-side
Allows testing the bahovior of a server-side code

Yes

You can test back-end components such as APIs using rest & soap clients, and databases using whatever client libraries were provided by the libraries that existed in those stacks

Yes

Since it is a complete testing system that can test any type of JavaScript code, it can test server-side behaviour and components as well
Fixtures
Allows defining a fixed, specific states of data (fixtures) that are test-local. This ensures specific environment for a single test

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

Using the cucumber extension aruba you can create fixures in two steps: 1.Create a fixtures-directory; 2.Create fixture files in this directory

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.

Yes

You can group your fixtures inside your fixtures directories

Licence
Licence type governing the use and redistribution of the software

MIT License

FreeBSD 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 all of RSpec’s supported mocking frameworks (RSpec, Mocha, RR, Flexmock)

Intern uses the Dojo Toolkit’s AMD loader. To mock, you should be able to just use the standard AMD 'map' feature, else you can use third party libraries like sinon.js
Grouping
Allows organizing tests in groups

No

Yes

You can group tests into Suites which may be specified as file paths or using glob expressions, there is typically one top-level suite per module.
Other
Other useful information about the testing framework