Lettuce vs Kiwi comparison of testing frameworks
What are the differences between Lettuce and Kiwi?

Lettuce

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

Kiwi

https://github.com/kiwi-bdd/Kiwi
Programming language

Python

Swift

Category

Unit Testing, Acceptance 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

Kiwi is a Behavior Driven Development library for iOS development

The goal behind Kiwi is to provide a BDD library that is simple to setup and use, and create tests that are more readable than what is possible with the bundled test framework.
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

Yes

Kiwi is an xUnit style framework
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

You can test front-end components with kiwi
Server-side
Allows testing the bahovior of a server-side code

Yes

Lettuce can test various server and database behaviours and interactions

Yes

You can test back-end components with kiwi
Fixtures
Allows defining a fixed, specific states of data (fixtures) that are test-local. This ensures specific environment for a single test

N/A

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

kiwi has a beforeEach(aBlock) which is run before every 'it' block in all enclosed contexts. Code that sets up the particular context should go here and afterEach(aBlock) which is run after every it block in all enclosed contexts
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

Yes

through the beforeAll(aBlock) and afterAll(aBlock) functions.
Licence
Licence type governing the use and redistribution of the software

Unknown

Proprietary, Open source

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

Kiwi has inbuilt support for stubs and mocks,including null mocks, class mocks, protocol mocks
Grouping
Allows organizing tests in groups

Yes

It allows grouping of tests

Yes

Kiwi uses the block syntax in iOS to define groups of assertions and share setup state between collections of tests
Other
Other useful information about the testing framework