Elixir Testing

Introduction to ExUnit

ExUnit is the built-in testing framework for Elixir, providing everything you need to write and run tests. It is tightly integrated with Elixir's tooling and is used to ensure your code behaves as expected. We'll explore how to set up and run tests using ExUnit, and how to leverage its features for comprehensive testing.

Setting Up ExUnit

ExUnit is included by default in new Elixir projects. You can start by creating a new project with mix new, which automatically sets up a test directory and an ExUnit configuration.

Writing Your First Test

Tests in ExUnit are defined in modules, typically located in the test directory, and named with a _test.exs suffix. Each test file should start with ExUnit.start() to ensure the test runner is properly initialized.

Running Tests with Mix

To execute your tests, use the mix test command. This will automatically find and run all test files in the test directory.

Understanding Assertions

Assertions are the heart of any test. They are expressions that evaluate to true or false, determining whether a test passes or fails. ExUnit provides a variety of assertion functions, such as assert, refute, and assert_raise.

Using Setup Callbacks

Setup callbacks allow you to define code that runs before each test in a module. This is useful for preparing the test environment or setting up common data structures.

Conclusion

ExUnit is a powerful tool for testing Elixir applications, offering all the necessary features to ensure your code behaves correctly. With its simple syntax and integration with Elixir's tools, writing and running tests becomes a seamless part of the development process.