Use docker-compose in Ruby tests

docker_compose.rb

module Docker::Compose
  class Session
    def wait(timeout = 10)
      Timeout.timeout(timeout) do
        loop do
          containers = ps
          return if containers
            .map { |container| running?(container.id) }
            .all?
        end
      end
    end


    def running?(container_id)
      cmd = @shell.run('docker', 'inspect', container_id, format: "{{.State.Running}}").join
      status, out, err = cmd.status, cmd.captured_output, cmd.captured_error

      unless status.success?
        raise Error.new("docker inspect #{container_id} -f {{.State.Running}}", status, out+err)
      end

      lines = out.split(/[\r\n]+/)
      return false if lines.empty?
      lines.first == "true"
    end
  end
end

gem.gemspec

  gem.add_development_dependency('docker-compose', '~> 1.1')

spec_helper.rb

compose = Docker::Compose.new
compose.up(detached: true)
compose.wait


at_exit { compose.down }