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

	Chai https://www.chaijs.com	pytest https://docs.pytest.org/en/latest/
Programming language	JavaScript	Python
Category	Unit Testing	Unit 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.	Pytest is the TDD 'all in one' testing framework for Python Pytest is a powerful Python testing framework that can test all and levels of software. It is considered by many to be the best testing framework in Python with many projects on the internet having switched to it from other frameworks, including Mozilla and Dropbox. This is due to its many powerful features such as ‘assert‘ rewriting, a third-party plugin model and a powerful yet simple fixture model.
xUnit Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.	N/A	No
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 pytest can test any part of the stack including front-end components
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 pytest is powerful enough to test database and server components 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 Pytest has a powerful yet simple fixture model that is unmatched in any other testing framework.
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 Pytest's powerful fixture model allows grouping of 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	Yes pytest has a hook function called pytest_generate_tests hook which is called when collecting a test function and one can use it to generate data
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 By either using unittest.mock or using pytest-mock a thin wrapper that provides mock functionality for pytest
Grouping Allows organizing tests in groups	N/A	Yes Tests can be grouped with pytest by use of markers which are applied to various tests and one can run tests with the marker applied
Other Other useful information about the testing framework