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

Kahlan

https://github.com/kahlan/kahlan

RSpec

https://rspec.info
Programming language

PHP

Ruby

Category

Unit Testing

Unit Testing, Intergration Testing

General info

Kahlan is a full-featured BDD testing framework

It is a full-featured BDD testing framework that embraces the KISS (Keep It Simple, Stupid) design principle. Kahlan makes it possible to write unit tests using the 'describe-it' syntax and requires at least PHP 5.5

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.
xUnit
Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.

No

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

Yes

Kahlan allows you to test front-end components and behaviour easily

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.
Server-side
Allows testing the bahovior of a server-side code

Yes

You can test individual back-end components using Kahlan

Yes

You can test server-side behaviour with Rspec
Fixtures
Allows defining a fixed, specific states of data (fixtures) that are test-local. This ensures specific environment for a single test

Yes

Fixtures can be defined by use of 'setUp()'method and cleaned using the 'tearDown()'method

Yes

RSpec does contain fixture methods
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 write group fixtures

Yes

Group fixture methods are supported
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

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

With Kahlan's stubbing system you are able to set stubs (like mocks) directly to your class methods (dynamic mocking)

Yes

Available through rspec-mocks gem.
Grouping
Allows organizing tests in groups

Yes

Kahlan allows you to group tests syntactically using a closure syntax. It has describe and context methods for grouping

Yes

Allows declaring example groups and contexts.
Other
Other useful information about the testing framework