testdouble.js vs RSpec comparison of testing frameworks
What are the differences between testdouble.js and RSpec?

	testdouble.js https://github.com/testdouble/testdouble.js	RSpec https://rspec.info
Programming language	JavaScript	Ruby
Category	Unit Testing, Intergration Testing	Unit Testing, Intergration Testing
General info	This library was designed to work for both Node.js and browser interpreters and it encourages the TDD (Test Driven Development) Test doubles can be used with conjuction of other test frameworks such as Jasmine, Jest, Chai, QUnit, Mocha, Tape etc.	Domain Specific Language (DSL) testing solution for Ruby code It focuses on empowering Test Driven Development (TDD). RSpec contains multiple smaller libraries, which may be independently used with other testing frameworks.
xUnit Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.	Yes It is compatible with xUnit and supportsxUnit XML output	Yes Yes, but it differs from more traiditional xUnit solutions. Its tests are written in a "Tests as Specification" manner. This means that the terminology used in RSpec is adjusted to a language more fitting for specification.
Client-side Allows testing code execution on the client, such as a web browser	No	Yes RSpec is used to primarily test the behaviour of applications or individual components so it can test front-end behaviour as well - you can use capybara gem with RSpec for that.
Server-side Allows testing the bahovior of a server-side code	Yes Testdouble is primarily used to test server-side functions, behaviours and components	Yes You can test server-side behaviour with Rspec
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 RSpec does contain fixture methods
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 Group fixture methods are supported
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 RSpec contains generators for example intergration_'test_name' which will save a spec inside the spec/requests folder
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 Testdouble includes inbuilt support for mocking	Yes Available through rspec-mocks gem.
Grouping Allows organizing tests in groups	N/A	Yes Allows declaring example groups and contexts.
Other Other useful information about the testing framework