Discussion on: Development environment for Elixir + Phoenix with Docker and Docker-compose

[Aleksi Holappa]

That Mix.env() is one way to achieve that. Personally I would still use String.replace/3, since Elixir 1.9 introduced a new way to configure your application without Mix dependency in your config-files.

I would do it this way:

test.exs

database_url = System.get_env("DATABASE_URL")

config :myapp, Myapp.Repo,
  url: String.replace(database_url, "?", "test"),
  pool: Ecto.Adapters.SQL.Sandbox

.env

DATABASE_URL=postgres://postgres:postgres@db:5432/myapp__?