RSpec vs Kiwi comparison of testing frameworks
What are the differences between RSpec and Kiwi?

RSpec

https://rspec.info

Kiwi

https://github.com/kiwi-bdd/Kiwi
Programming language

Ruby

Swift

Category

Unit Testing, Intergration Testing

Unit Testing

General info

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.

Kiwi is a Behavior Driven Development library for iOS development

The goal behind Kiwi is to provide a BDD library that is simple to setup and use, and create tests that are more readable than what is possible with the bundled test framework.
xUnit
Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.

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.

Yes

Kiwi is an xUnit style framework
Client-side
Allows testing code execution on the client, such as a web browser

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.

Yes

You can test front-end components with kiwi
Server-side
Allows testing the bahovior of a server-side code

Yes

You can test server-side behaviour with Rspec

Yes

You can test back-end components with kiwi
Fixtures
Allows defining a fixed, specific states of data (fixtures) that are test-local. This ensures specific environment for a single test

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.

Yes

Group fixture methods are supported

Yes

kiwi has a beforeEach(aBlock) which is run before every 'it' block in all enclosed contexts. Code that sets up the particular context should go here and afterEach(aBlock) which is run after every it block in all enclosed contexts
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

Yes

through the beforeAll(aBlock) and afterAll(aBlock) functions.
Licence
Licence type governing the use and redistribution of the software

MIT License

Proprietary, Open source

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

Available through rspec-mocks gem.

Yes

Kiwi has inbuilt support for stubs and mocks,including null mocks, class mocks, protocol mocks
Grouping
Allows organizing tests in groups

Yes

Allows declaring example groups and contexts.

Yes

Kiwi uses the block syntax in iOS to define groups of assertions and share setup state between collections of tests
Other
Other useful information about the testing framework