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