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

ExUnit

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

Concordion

https://concordion.org/
Programming language

Elixir

Java

Category

Unit Testing

General info

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

Concordion is a tool used to write and manage automated acceptance tests in Java based projects

Concordion specifications are written in Markdown, HTML or Excel and then instrumented with special links, attributes or comments respectively. When the corresponding test fixture class is run, Concordion interprets the instrumentation to execute the test. Concordion lets you write them in normal language using paragraphs, tables and proper punctuation. This makes specification more natural to read and write, and helps everyone to understand and agree about what a feature is supposed to do.
xUnit
Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.

Yes

xUnit has the ExUnit framework as an instance

No

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

Yes

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

Yes

You can specify tests for front-end components and functionality with concordion
Server-side
Allows testing the bahovior of a server-side code

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

Yes

You can test server-side components and functionality with concordion.
Fixtures
Allows defining a fixed, specific states of data (fixtures) that are test-local. This ensures specific environment for a single test

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

Yes

Concordion contains fixtures which correspond to a specific instrumentation within the code. That is when specifications are written they are instrumented with special links, attributes or comments which are then run with their corresponding fixtures
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

Group fixures are possible with this library

Yes

One can group fixtures in concordion
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

Generators are found in the StreamData module

N/A

Licence
Licence type governing the use and redistribution of the software

Apache License 2.0

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)

Yes

Mocks are available for use with ExUnit through the Mock module. Also available through the use of third party libraries like mecktest

Yes

By use of third party libraries like mockito
Grouping
Allows organizing tests in groups

Yes

Using the 'describe' function which goups tests together. Every describe block recieves a name which is used as a prefix for upcoming tests

Yes

One can group tests into suites
Other
Other useful information about the testing framework