Test Drive Your Dockerfiles with RSpec and ServerSpec

Dockerfile

FROM ubuntu:14.04
MAINTAINER Mason Fischer <mason@thoughtbot.com>
RUN apt-get update && apt-get install -y nodejs

Dockerfile_spec.rb

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

@masonforest great blog post! Any suggestions on how to go about removing the images after the tests get run? I've tried it this way, but this doesn't seem right (or to work!)

https://github.com/tfhartmann/docker-puppetserver/blob/73935b2a3aaedca27e3c0984823912b565f39546/spec/Dockerfile_spec.rb#L14-L16

Just calling out: it's important to specify that you should use the docker-api gem. The docker gem is not the right one to use. But confusingly, the require statement is correct!
require "docker"

@cjcjameson you just saved me a lot of time buddy, thx. and thx @masonforest !

Oh my! The docker-api gem! what a difference that makes! @masonforest - do you think you can update the article to call this out? it would have saved me a bunch of time!

@tfhartmann : I add this to my specs:

after(:all) do
    @image.remove(:force => true)
end

In the example you build the image only. I assume ServerSpec is starting the container and stopping by the end of the test. How can you pass arguments to the container such as environment variables, commands, volumes, etc?

Hello, this is my version of docker:

$ docker -v                                                                     
Docker version 1.11.1

I can't using rspec and always getting this message:

$ bundle exec rspec spec                                             
No examples found.


Finished in 0.00098 seconds (files took 1.23 seconds to load)
0 examples, 0 failures

this is my directory structure:

$ tree .                                                                          ‹ruby-2.3.0›
.
├── Dockerfile
├── run
└── spec
    └── Dockerfile_spec.rb

1 directory, 3 files