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

	ExUnit https://hexdocs.pm/ex_unit/ExUnit.html	Spek https://www.spekframework.org/
Programming language	Elixir	Kotlin
Category	Unit Testing	Acceptance Testing, 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	Spek is a specification framework for Kotlin Spek is a Kotlin-based Specification Testing framework for the JVM. It works as a JUnit 5 Test Engine meaning that we can easily plug it into any project that already uses JUnit 5 to run alongside any other tests that we might have.
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 Yes you can test front-end behaviour by writing specifications to test front-end functionality. Developers can also write unit tests for individual front-end components.
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 back-end behaviour and componets by writing specifications to test back-end functionality and unit tests for individual back-end components
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 Fixtures are available in spek through functions suchas beforeEachTest() and afterEachTest()
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 spek has group fixtures available through the beforeGroup() and afterGroup() functions
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	Modified BSD 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)	Yes Mocks are available for use with ExUnit through the Mock module. Also available through the use of third party libraries like mecktest	Yes You can use the third party library mockito-kotlin
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 Tests are written using nested lambdas, each scope (level) can either be a group or a test
Other Other useful information about the testing framework