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

AVA

https://github.com/avajs/ava

ExUnit

https://hexdocs.pm/ex_unit/ExUnit.html
Programming language

JavaScript

Elixir

Category

Unit Testing, Intergration Testing

Unit 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

Unit testing framework for Elixir.

Elixir comes bundled with ExUnit allowing developers to use all elixir features without compromising unit tests. It uses a TDD workflow, and shows one message per test
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

Yes

xUnit has the ExUnit framework as an instance
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

Front-end code can be tested using ExUnit, Phoenix front-end framework for Elixir uses ExUnit as the default testing framework
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

ExUnit tests backend code. Typically Unit tests will be written not to interact with the browser, but with ExUnit you can test whichever part of your application
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

ExUnit has a library called ExUnitFixtures fixtures are functions that are run before a test is run to setup the test environment or provide the test with data
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

Group fixures are possible with this library
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

Yes

Generators are found in the StreamData module
Licence
Licence type governing the use and redistribution of the software

MIT License

Apache License 2.0

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.

Yes

Mocks are available for use with ExUnit through the Mock module. Also available through the use of third party libraries like mecktest
Grouping
Allows organizing tests in groups

No

There is no support for grouping tests

Yes

Using the 'describe' function which goups tests together. Every describe block recieves a name which is used as a prefix for upcoming tests
Other
Other useful information about the testing framework