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

Chai

https://www.chaijs.com

WebdriverIO

https://webdriver.io/
Programming language

JavaScript

JavaScript

Category

Unit Testing

Browser Automation, Unit Testing, Functional Testing

General info

Chai is a BDD / TDD assertion library for Node.js and the browser that can be paired with any JavaScript testing framework.

Chai is an assertion library, similar to Node's built-in assert and makes testing easier by giving you many assertions you can run against your code. It also includes a robust Plugin architecture for extending Chai's assertions and interfaces.

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.

N/A

Yes

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

Yes

Chai can be used in a browser environment to test front-end components and functionality

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

Chai is used in a Node.JS environment to test server behaviour and functionality

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

N/A

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.

N/A

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.

Yes

By using chai-spec-generator plugin which will generate chai test specs from a JavaScript object

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)

Yes

By using by using a third party library like chai-jest-mocks which is a chai plugin that adds assertions for jest mock functions. You can also use sinon.js

Yes

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

N/A

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