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

	Spock http://spockframework.org/	RSpec https://rspec.info
Programming language	Java	Ruby
Category	Unit Testing	Unit Testing, Intergration Testing
General info	Spock is a testing and specification framework for Java and Groovy applications Spock has a highly expressive specification language, and due to its JUnit runner, Spock is compatible with most IDEs, build tools, and continuous integration servers.Spock is inspired from JUnit, RSpec, jMock, Mockito, Groovy, Scala, Vulcans among others	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 Spock tests front-end components and functionality by unit testing individual classes and functions	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 Spock tests back-end components and functionality by unit testing individual classes and functions	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 Spock contains four methods for setting up environments :setup() (run before every feature method), cleanup() (run after every feature method), setupSpec() (run before the first feature method), cleanupSpec() (run after the last feature method)	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 You can use the fixture methods to setup environments for groups of tests.	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	Apache License 2.0	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 Spock has inbuilt mocking capabilities and has no need for external libraries	Yes Available through rspec-mocks gem.
Grouping Allows organizing tests in groups	Yes You can create suites manually in spock	Yes Allows declaring example groups and contexts.
Other Other useful information about the testing framework