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

Cucumber

https://github.com/cucumber/cucumber-ruby

Selenium

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

Ruby

Python

Category

Acceptance Testing

Web Automation

General info

An automation tool for Behavior-Driven Development

The specifications are written in plain texts, which allows them to be easily understandable for all stakeholders. Cucumber Framework also supports languages beyond Ruby e.g. Java, JavaScript and Scala.

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

You can test the front-end part like the GUI using cucumber and selenium, they integrate well to test your front-end.

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

You can test back-end components such as APIs using rest & soap clients, and databases using whatever client libraries were provided by the libraries that existed in those stacks

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

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

Using the cucumber extension aruba you can create fixures in two steps: 1.Create a fixtures-directory; 2.Create fixture files in this directory

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.

Yes

You can group your fixtures inside your fixtures directories

Yes

By using a library such as Faker or Fake-factory
Licence
Licence type governing the use and redistribution of the software

MIT License

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

By using all of RSpec’s supported mocking frameworks (RSpec, Mocha, RR, Flexmock)

Yes

It includes support for mocking
Grouping
Allows organizing tests in groups

No

Yes

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