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

	Spek https://www.spekframework.org/	RSpec https://rspec.info
Programming language	Kotlin	Ruby
Category	Acceptance Testing, Unit Testing	Unit Testing, Intergration Testing
General info	Spek is a specification framework for Kotlin Spek is a Kotlin-based Specification Testing framework for the JVM. It works as a JUnit 5 Test Engine meaning that we can easily plug it into any project that already uses JUnit 5 to run alongside any other tests that we might have.	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.	No	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	Yes Yes you can test front-end behaviour by writing specifications to test front-end functionality. Developers can also write unit tests for individual front-end components.	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 You can test back-end behaviour and componets by writing specifications to test back-end functionality and unit tests for individual back-end 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	Yes Fixtures are available in spek through functions suchas beforeEachTest() and afterEachTest()	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 spek has group fixtures available through the beforeGroup() and afterGroup() functions	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.	N/A	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	Modified BSD 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 use the third party library mockito-kotlin	Yes Available through rspec-mocks gem.
Grouping Allows organizing tests in groups	Yes Tests are written using nested lambdas, each scope (level) can either be a group or a test	Yes Allows declaring example groups and contexts.
Other Other useful information about the testing framework