Testcontainers

Testcontainers is an Elixir library that supports ExUnit tests, providing lightweight, throwaway instances of common databases, or anything else that can run in a Docker container.

It supports Testcontainers Desktop, but doesn’t need it to run. It will find and pick up a docker engine that works every time it runs.

Let me show you its features

In its basic form Testcontainers can used like this:

{:ok, _} = Testcontainers.start_link()
config = %Testcontainers.Container{image: "redis:latest"}
{:ok, container} = Testcontainers.start_container(config)

But the most interesting usage for Elixir is the Ecto module, which lets you run tests without having a postgres (or mysql) container running (see the README section for this advanced usage).

You can also spin up a throwaway container in a single ExUnit test:

container(:redis, Testcontainers.RedisContainer.new())

or shared container for multiple tests

container(:redis, Testcontainers.RedisContainer.new(), shared: true)

How it works

It has a dependency on an autogenerated elixir library for the docker engine api. The complex logic for calling out to docker is hidden inside that library.