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

Behat

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

WebdriverIO

https://webdriver.io/
Programming language

PHP

JavaScript

Category

Functional/Acceptance Testing

Browser Automation, Unit Testing, Functional Testing

General info

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

WebdriverIO is the next-gen WebDriver test framework for Node.js made upon Selenium

WebdriverIO is written in JavaScript and uses Selenium under the hood. It also comes with its own inbuilt test runner and supports other testing frameworks like Jasmine, Cucumber, and Mocha
xUnit
Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.

No

Yes

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

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.

Yes

WebdriverIO allows the use of advanced CSS selectors and makes it easy to find elements for front-end testing
Server-side
Allows testing the bahovior of a server-side code

Yes

Behat can be used for Data Integrity Testing to verify that database operations are functioning properly

Yes

It can be used to test server side behaviour and functionality
Fixtures
Allows defining a fixed, specific states of data (fixtures) that are test-local. This ensures specific environment for a single test

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.

Yes

WebdriverIO supports the creation of fixtures
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

Behat allows for group fixtures

Yes

WebdriverIO supports the creation of 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.

By use of third party libraries like moodle-behat-generators

N/A

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)

By using third party libraries like Mock and Prophecy

Yes

It contains a mocking service called 'wdio-wiremock-service'
Grouping
Allows organizing tests in groups

Yes

You can use tags to group features and scenarios together, independent of your file and directory structure

Yes

WebdriverIO allows one to build test suites, you can run these test in parallel and organize them by adjusting the 'maxInstances' property in your config file
Other
Other useful information about the testing framework