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

PHPUnit

https://phpunit.de/

Cucumber

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

PHP

Ruby

Category

Unit Testing

Acceptance 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.

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.
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

No

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

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

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

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

You can group your fixtures inside your fixtures directories
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

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

No

Other
Other useful information about the testing framework