Unit.js vs SpecFlow comparison of testing frameworks
What are the differences between Unit.js and SpecFlow?

Unit.js

https://unitjs.com/

SpecFlow

https://specflow.org/
Programming language

JavaScript

.NET

Category

Unit Testing, End-to-End Testing

Acceptance Testing

General info

An assertion library for JavaScript (similar to chai.js)

It works with any test runner and unit testing framework like Mocha, Jasmine, Karma, protractor (E2E test framework for Angular apps) and QUnit.

SpecFlow is a test automation solution for .NET

SpecFlow is a test automation solution for .NET which follows the BDD paradigm, and is part of the Cucumber family. SpecFlow tests are written with Gherkin, using the official Gherkin parser which allows you to write test cases using natural languages and supports over 70 languages.
xUnit
Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.

No

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

Yes

Unit.js runs in the browser to test front-end components

Yes

Front-end behaviour is tested. With specflow specifications of the expected behaviours are made and specflow tests against this
Server-side
Allows testing the bahovior of a server-side code

Yes

Unit.js runs in nodejs to test server-side behaviour

Yes

Back-end behaviour is tested. Specifications of the expected behaviours are made and specflow tests against them
Fixtures
Allows defining a fixed, specific states of data (fixtures) that are test-local. This ensures specific environment for a single test

Yes

Unit.js provides Test fixtures for running testsThis is one of its features

Yes

BeforeTestRun and AfterTestRun are executed once for each thread which is a limitation of the current architecture.
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

With Unit.js you can group your 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.

Yes

SpecFlow contains a generator component. The SpecFlow IDE integration tries to locate the generator component in your project structure, in order to use the generator version matching the SpecFlow runtime in your project
Licence
Licence type governing the use and redistribution of the software

GNU

BSD 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)

N/A

Yes

Specflow intergrates well with mock to give it excellent mocking capabilities
Grouping
Allows organizing tests in groups

N/A

Yes

You can create test suites with specflow
Other
Other useful information about the testing framework