Lettuce vs Cypress.io comparison of testing frameworks
What are the differences between Lettuce and Cypress.io?

Lettuce

https://pypi.org/project/lettuce/

Cypress.io

https://www.cypress.io/
Programming language

Python

JavaScript

Category

Unit Testing, Acceptance Testing

End-to-End Testing, Intergration Testing, Unit Testing

General info

Lettuce is a BDD testing tool for Python

Lettuce is a testing tool for Python which is inspired by Ruby's Cucumber that supports Gherkin. It can execute plain-text functional descriptions as automated tests for Python projects just like Cucumber does for Ruby

Cypress users are typically developers or QA engineers building web applications using modern JavaScript frameworks. This is the top tier UI automation framework which outsmarts Selenium based frameworks in most of the aspects!

Cypress enables you to write all types of tests: 1. End-to-end tests; 2. Integration tests; 3. Unit tests; 4. Cypress can test anything that runs in a browser; Apart from that Cypress provides the Dashboard facility for CI/CD
xUnit
Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.

No

However It can generate xml results for behaviour tests xUnit style

No

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

Yes

By integrating Lettuce with Selenium’s Python bindings, you have a robust framework for testing Django applications. It can test front-end behaviour

Yes

This is the primary goal of Cypress, it tests anything that runs in a browser and works to build great user experience that is it tests the applications flow from beginning to end from a user perspective. It is built to handle modern JavaScript frameworks especially well and also works equally well on older server rendered pages or applications
Server-side
Allows testing the bahovior of a server-side code

Yes

Lettuce can test various server and database behaviours and interactions

Yes

Although Cypress is not a general automation framework, nor is it a unit testing framework for your back-end services, It can test back-end behaviours for example using cy.task() command which provides a way for running Node code, so you can take actions necessary for your tests outside of the scope of Cypress
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

Cypress has inbuilt fixtures capabilities or example using the command 'cy.fixture(filePath)' loads a fixed set of data located in a file
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

Cypress can create group fixtures using the 'cy.fixture' command
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 a third party library

N/A

Licence
Licence type governing the use and redistribution of the software

Unknown

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 adding the lettuce-tools library one has access to the Mock module to implement a configurable http REST mock.

Yes

Cypress comes built in with the ability to stub and spy with cy.stub(), cy.spy(), It also automatically bundles 'sinon', 'lolex' and 'sinon-chai' which all work to give Cypress mocking capabilities
Grouping
Allows organizing tests in groups

Yes

It allows grouping of tests

Yes

Cypress allows you to configure tests into groups however there is no way currently to run the groups
Other
Other useful information about the testing framework