A type safe library to define and run test dependencies using scala and Docker containers.

Not feature-complete yet, will publish a first release soon!

Scala's strong type system, when used properly, can help avoiding a range of obvious bugs (e.g. null pointer exceptions), often removing the need for pedantic, low-level unit testing. However, we still find highly valuable testing the integration of several software components. It is in fact at this level that we spot most bugs (e.g. serialisation/deserialisation, missing configuration values, SQL queries working differently across vendors, race conditions, etc.).

Recently, we have started using Docker to streamline the way we run this type of tests, both on our development machines and on our continuous integration environment. By allowing us to reproduce a realistic production environment with great flexibility and speed, containers are helping us increase our confidence in our testing and continuous delivery process.

The library currently consists of the following modules:

• An "algebra" to define test dependencies (aka Service) as aggregates of one or several Container.
• An InMemoryServiceRegistry that can automatically assign available host ports to a service containers.
• A Scheduler, which provides a simple interface suitable to repeatedly check if a service is ready
• "Interpreters" to setup/check/teardown services using Docker as container technology, and scala.concurrent.Future or cats.effect.IO as the effect system.

• core: the core algebra, with built-in support for scala.concurrent.Future.
• core-io: optional support for cats.effect.IO
• docker: a docker interpreter for the core algebra.