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

AVA

https://github.com/avajs/ava

Behat

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

JavaScript

PHP

Category

Unit Testing, Intergration Testing

Functional/Acceptance Testing

General info

Futuristic, new, fast and concurrent JavaScript test runner with simple test syntax

AVA is a test runner for Node.js with a concise API, detailed error output. JS is a single-threaded but Node.JS is a parallel due to it's async behaviour. Ava leverages that and it can run tests concurrently

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
xUnit
Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.

No

However Ava supports the TAP format which allows us to use the tap-xunit reporter to produce xUnit (JUnit) XML

No

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

Yes

You can write tests for the DOM with Ava, testing front-end components is easy with Ava

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.
Server-side
Allows testing the bahovior of a server-side code

Yes

Ava utilizes the async I/O nature of Node and runs concurrent tests on NodeJs applications' back-endsA node server can have its endpoints tested with Ava

Yes

Behat can be used for Data Integrity Testing to verify that database operations are functioning properly
Fixtures
Allows defining a fixed, specific states of data (fixtures) that are test-local. This ensures specific environment for a single test

Yes

Using Ava's ava-fixture library it supports fixtures

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.
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

Ava has support for group fixtures

Yes

Behat allows for 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.

N/A

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

AVA has no mocking built in, to mock functions you can use third party libraries like Sinon.js.

By using third party libraries like Mock and Prophecy
Grouping
Allows organizing tests in groups

No

There is no support for grouping tests

Yes

You can use tags to group features and scenarios together, independent of your file and directory structure
Other
Other useful information about the testing framework