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

	PHPUnit https://phpunit.de/	RSpec https://rspec.info
Programming language	PHP	Ruby
Category	Unit Testing	Unit Testing, Intergration Testing
General info	PHPUnit is a unit testing framework for the PHP programming language PHPUnit is a programmer-oriented testing framework and is an instance of the xUnit architecture for unit testing frameworks.	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.	Yes It's an instance of the xUnit architecture for unit testing frameworks	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 It can perform Unit tests and can test various front-end components and behaviours	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 By performing unit tests on singular back-end components	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 By use of a setup code. The setup code consists of two Important template functions, the 'setUp()' function (called to create the objects to be tested) and 'tearDown()' function (called to cleanup the objects which you tested)	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 It does support 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	Creative Commons Attribution 3.0 Unported 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 One of its main features is that PHPUnit comes with out of the box support for Mock objects	Yes Available through rspec-mocks gem.
Grouping Allows organizing tests in groups	Yes It allows grouping of tests and by using the @group annotation one can tag a test to belong to one or more groups	Yes Allows declaring example groups and contexts.
Other Other useful information about the testing framework