require "serverspec" require "docker" describe "Dockerfile" do image = Docker::Image.build_from_dir('.') set :os, family: :debian set :backend, :docker set :docker_image, image.id it "installs the right version of Ubuntu" do expect(os_version).to include("Ubuntu 14") end it "installs required packages" do expect(package("nodejs")).to be_installed end def os_version command("lsb_release -a").stdout end end