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

Shoulda

https://github.com/thoughtbot/shoulda

ExUnit

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

Ruby

Elixir

Category

Unit Testing

General info

Meta gem containing Shoulda Context and Shoulda Matchers

Shoulda contains two other gems: Should Context and Shoulda Matchers. Should Context allows better naming and grouping of your tests. Shoulda Matchers provides a set of "matchers", i.e. methods that allow you to write much more concise assertions.

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

Yes

xUnit has the ExUnit framework as an instance
Client-side
Allows testing code execution on the client, such as a web browser

N/A

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

N/A

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

N/A

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.

N/A

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)

N/A

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

Yes

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

Shoulda Context is compatible with Minitest and Test::Unit. Shoulda Matchers is compatible with RSpec and Minitest.