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

	Spock http://spockframework.org/	XCTest https://developer.apple.com/documentation/xctest
Programming language	Java	Swift
Category	Unit Testing	Unit Testing, Performance 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	XCTest is the default testing framework for unit tests, performance tests, and some level of UI tests for iOS apps. XCTest framework is a testing framework that enables developers write basic unit tests, performance tests, and some level of UI tests for iOS apps.
xUnit Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.	No	Yes Yes, it 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 Developers can test individual front-end components with XCTest
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 Yes, developers can test individual back-end components with XCTest
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 XCTest contains setup() and teardown() fixture methods for setting up and destroying test environments
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 fixtures are available in XCTest
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	Apache License 2.0
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 create protocol mocks and class mocks with libraries such as MockFive or Cuckoo
Grouping Allows organizing tests in groups	Yes You can create suites manually in spock	Yes Developers can define test suites from the XCTestSuite class
Other Other useful information about the testing framework