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

Spock

http://spockframework.org/

Selenium

https://pypi.org/project/selenium/
Programming language

Java

Python

Category

Unit Testing

Web Automation

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

Selenium is an open source tool used to test web applications

Selenium is a powerful testing tool which can send standard Python commands to different browsers, despite variations in browser design. It also provides extensions to emulate user interaction with browsers, a distribution server for scaling browser allocation, and the infrastructure for implementations of the W3C WebDriver specification that lets you write interchangeable code for all major web browsers
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

It is primarily a browser automation tool which tests front-end components and functionality
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

It can perform Unit tests and can test various components and behaviours in the backend using a BDD or TDD approach
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

By writing your Selenium WebDriver tests in PyTest, this gives you access to Pytest's powerful fixture model
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

One can group fixtures if accessing Pytest's fixture model
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

By using a library such as Faker or Fake-factory
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

It includes support for mocking
Grouping
Allows organizing tests in groups

Yes

You can create suites manually in spock

Yes

By using the TestNG feature with which we can create groups and maintain them easily
Other
Other useful information about the testing framework