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

Spock

http://spockframework.org/

Kiwi

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

Java

Swift

Category

Unit 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

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.

No

Yes

Kiwi is an xUnit style framework
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

You can test front-end components with kiwi
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 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

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)

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

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.

N/A

Yes

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

Apache License 2.0

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

Spock has inbuilt mocking capabilities and has no need for external libraries

Yes

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

Yes

You can create suites manually in spock

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