RSpec vs Behat comparison of testing frameworks
What are the differences between RSpec and Behat?

RSpec

https://rspec.info

Behat

https://docs.behat.org/en/latest/
Programming language

Ruby

PHP

Category

Unit Testing, Intergration Testing

Functional/Acceptance Testing

General info

Domain Specific Language (DSL) testing solution for Ruby code

It focuses on empowering Test Driven Development (TDD). RSpec contains multiple smaller libraries, which may be independently used with other testing frameworks.

Behat is an open source Behavior-Driven Development framework for PHP.

Behat uses the StoryBDD subtype of behaviour-driven development (the other subtype is SpecBDD); This means the tests we write with Behat look rather like stories than code. It is inspired by Ruby's Cucumber
xUnit
Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.

Yes

Yes, but it differs from more traiditional xUnit solutions. Its tests are written in a "Tests as Specification" manner. This means that the terminology used in RSpec is adjusted to a language more fitting for specification.

No

Client-side
Allows testing code execution on the client, such as a web browser

Yes

RSpec is used to primarily test the behaviour of applications or individual components so it can test front-end behaviour as well - you can use capybara gem with RSpec for that.

Yes

To enable Behat to test a website, you need to add Mink and a browser emulator (selenium maybe, though slow) to the mix. Mink methods are the connector between Behat and an extensive list of available drivers, and they provide a consistent testing API.
Server-side
Allows testing the bahovior of a server-side code

Yes

You can test server-side behaviour with Rspec

Yes

Behat can be used for Data Integrity Testing to verify that database operations are functioning properly
Fixtures
Allows defining a fixed, specific states of data (fixtures) that are test-local. This ensures specific environment for a single test

Yes

RSpec does contain fixture methods

Yes

One can use the 'Doctrinefixturesbundle' to create the required fixture loaders and load them in our Behat scenarios when required, using the 'BeforeScenario' hook.
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

Group fixture methods are supported

Yes

Behat allows for group fixtures
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

RSpec contains generators for example intergration_'test_name' which will save a spec inside the spec/requests folder

By use of third party libraries like moodle-behat-generators
Licence
Licence type governing the use and redistribution of the software

MIT License

MIT License

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

Available through rspec-mocks gem.

By using third party libraries like Mock and Prophecy
Grouping
Allows organizing tests in groups

Yes

Allows declaring example groups and contexts.

Yes

You can use tags to group features and scenarios together, independent of your file and directory structure
Other
Other useful information about the testing framework