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

	Spock http://spockframework.org/	Spek https://www.spekframework.org/
Programming language	Java	Kotlin
Category	Unit Testing	Acceptance Testing, Unit 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	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.
xUnit Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.	No	No
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 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.
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 back-end behaviour and componets by writing specifications to test back-end functionality and unit tests for individual back-end components
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 Fixtures are available in spek through functions suchas beforeEachTest() and afterEachTest()
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 spek has group fixtures available through the beforeGroup() and afterGroup() functions
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	N/A
Licence Licence type governing the use and redistribution of the software	Apache License 2.0	Modified 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)	Yes Spock has inbuilt mocking capabilities and has no need for external libraries	Yes You can use the third party library mockito-kotlin
Grouping Allows organizing tests in groups	Yes You can create suites manually in spock	Yes Tests are written using nested lambdas, each scope (level) can either be a group or a test
Other Other useful information about the testing framework