diff --git a/.gitignore b/.gitignore
index a54aa97..3b626b8 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,6 +5,7 @@
 /spec/fixtures/modules/*
 !/spec/fixtures/modules/apt
 !/spec/fixtures/modules/apt/*
+/log
 /.vagrant/
 /.bundle/
 /coverage/
diff --git a/Gemfile b/Gemfile
index 8925a90..a2756c4 100644
--- a/Gemfile
+++ b/Gemfile
@@ -11,3 +11,10 @@ group :test do
   gem "rspec-puppet-facts"
   gem "mocha"
 end
+
+group :system_tests do
+  gem 'beaker',              :require => false
+  gem 'beaker-rspec',        :require => false
+  gem 'beaker_spec_helper',  :require => false
+  gem 'serverspec',          :require => false
+end
diff --git a/README.md b/README.md
index 7431038..2173d7e 100644
--- a/README.md
+++ b/README.md
@@ -23,12 +23,13 @@
   * [apt::preseeded_package](#apt-preseeded_package)
   * [apt::sources_list](#apt-sources_list)
   * [apt::key](#apt-key)
-  * [apt::key::plain](#apt-key-plain)
+  * [`apt::key::plain`](#apt-key-plain)
   * [apt::upgrade_package](#apt-upgrade_package)
 * [Resources](#ressources)
   * [File\['apt_config'\]](#fileapt_config)
   * [Exec\['apt_updated'\]](#execapt_updated)
 * [Tests](#tests)
+  * [Acceptance Tests](#acceptance-tests)
 * [Licensing](#licensing)
 
 
@@ -55,7 +56,7 @@ Ubuntu support is lagging behind but not absent either.
  * The default value of the `$repos` parameter was removed since the logic is
    now in the `apt::params` class. If you have explicitly set `$repos` to
    'auto' in your manifests, you should remove this.
-
+ 
  * The `disable_update` parameter has been removed. The main apt class
    defaults to *not* run an `apt-get update` on every run anyway so this
    parameter seems useless.
@@ -79,17 +80,16 @@ Ubuntu support is lagging behind but not absent either.
    instantiating the class with those variables instead. For example, if you 
    had the following in your manifests:
 
-    $apt_debian_url = 'http://localhost:9999/debian/'
-    $apt_use_next_release = true
-    include apt
+       $apt_debian_url = 'http://localhost:9999/debian/'
+       $apt_use_next_release = true
+       include apt
  
    you will need to remove the variables, and the include and instead do
    the following:
 
-    class {
-      'apt':
-        debian_url       => 'http://localhost:9999/debian/',
-        use_next_release => true;
+    class { 'apt':
+      debian_url       => 'http://localhost:9999/debian/',
+      use_next_release => true;
     }
 
    previously, you could manually set `$lsbdistcodename` which would enable forced
@@ -101,26 +101,24 @@ Ubuntu support is lagging behind but not absent either.
    you to trigger upgrades:
 
     include apt::dist_upgrade
-    class {
-      'apt':
-        codename => 'wheezy',
-        notify   => Exec['apt_dist-upgrade'];
+    class { 'apt':
+      codename => 'wheezy',
+      notify   => Exec['apt_dist-upgrade'];
     }
 
  * the `apticron` class has been moved to a parameterized class.  if you were
    including this class before, you will need to move to instantiating the
    class instead. For example, if you had the following in your manifests:
 
-    $apticron_email = 'foo@example.com'
-    $apticron_notifynew = '1'
-    ... any $apticron_* variables
-    include apticron
+       $apticron_email = 'foo@example.com'
+       $apticron_notifynew = '1'
+       ... any $apticron_* variables
+       include apticron
 
    you will need to remove the variables, and the include and instead do the
    following:
 
-    class {
-    'apt::apticron':
+    class { 'apt::apticron':
       email     => 'foo@example.com',
       notifynew => '1';
     }
@@ -130,16 +128,15 @@ Ubuntu support is lagging behind but not absent either.
    to move to instantiating the class with those variables instead. For example,
    if you had the following in your manifests:
 
-    $apt_listchanges_email = 'foo@example.com'
-    ... any $apt_listchanges_* variables
-    include apt::listchanges
+       $apt_listchanges_email = 'foo@example.com'
+       ... any $apt_listchanges_* variables
+       include apt::listchanges
 
    you will need to remove the variables, and the include and instead do the
    following:
  
-    class {
-      'apt::listchanges':
-        email => 'foo@example.com';
+    class { 'apt::listchanges':
+      email => 'foo@example.com';
     }
    
  * the `apt::proxy_client` class has been moved to a paramterized class. if you
@@ -147,18 +144,17 @@ Ubuntu support is lagging behind but not absent either.
    to move to instantiating the class with those variables instead. For example,
    if you had the following in your manifests:
 
-    $apt_proxy = 'http://proxy.domain'
-    $apt_proxy_port = 666
-    include apt::proxy_client
+       $apt_proxy = 'http://proxy.domain'
+       $apt_proxy_port = 666
+       include apt::proxy_client
 
    you will need to remove the variables, and the include and instead do the
    following:
 
-    class {
-      'apt::proxy_client':
-        proxy => 'http://proxy.domain',
-        port  => '666';
-    }
+       class { 'apt::proxy_client':
+         proxy => 'http://proxy.domain',
+         port  => '666';
+       }
 
 
 # Requirements<a name="requirements"></a>
@@ -570,7 +566,7 @@ use `apt::key::plain`.
 The `.gpg` extension is compulsory for `apt` to pickup the key properly.
 
 
-## apt::key::plain<a name="apt-key-plain"></a>
+## `apt::key::plain`<a name="apt-key-plain"></a>
 
 Deploys a secure apt OpenPGP key. This usually accompanies the
 sources.list snippets above for third party repositories. For example,
@@ -647,11 +643,33 @@ To run pupept rspec tests:
     bundle install --path vendor/bundle
     bundle exec rake spec
 
+Verbose Output:
+ 
+    bundle exec rake spec SPEC_OPTS='--format documentation'
+
 Using different facter/puppet versions:
 
     FACTER_GEM_VERSION=1.6.10 PUPPET_GEM_VERSION=2.7.23 bundle install --path vendor/bundle
     bundle exec rake spec
 
+## Acceptance Tests<a name="acceptance-tests"></a>
+
+At the moment, we use [beaker together with docker](https://github.com/puppetlabs/beaker/blob/master/docs/Docker-Support.md)
+to do acceptance testing.
+Be sure to have a recent docker version installed.
+
+List configured nodesets:
+
+    bundle exec rake beaker_nodes
+
+Run tests on default node (Debian Jessie):
+
+    bundle exec rake beaker
+
+Run different nodeset:
+
+    BEAKER_set="debian-8-x86_64-docker" bundle exec rspec spec/acceptance/*_spec.rb
+ 
 
 # Licensing<a name="licensing"></a>
 
diff --git a/manifests/preseeded_package.pp b/manifests/preseeded_package.pp
index 3ef0687..162ade7 100644
--- a/manifests/preseeded_package.pp
+++ b/manifests/preseeded_package.pp
@@ -1,3 +1,4 @@
+# Install a package with a preseed file to automatically answer some questions.
 define apt::preseeded_package (
   $ensure = 'installed',
   $content = ''
@@ -10,7 +11,9 @@ define apt::preseeded_package (
 
   file { $seedfile:
     content => $real_content,
-    mode    => '0600', owner => root, group => root,
+    mode    => '0600',
+    owner   => 'root',
+    group   => 0,
   }
 
   package { $name:
diff --git a/manifests/sources_list.pp b/manifests/sources_list.pp
index 0ee068d..7565bce 100644
--- a/manifests/sources_list.pp
+++ b/manifests/sources_list.pp
@@ -1,3 +1,4 @@
+# Configure an apt source
 define apt::sources_list (
   $ensure = 'present',
   $source = '',
@@ -22,7 +23,9 @@ define apt::sources_list (
   # apparently doesn't.
   file { "/etc/apt/sources.list.d/${realname}.list":
     ensure => $ensure,
-    owner  => root, group => 0, mode => '0644',
+    mode   => '0644',
+    owner  => 'root',
+    group  => 0,
     notify => Exec['apt_updated'],
   }
 
diff --git a/manifests/upgrade_package.pp b/manifests/upgrade_package.pp
index 30572c9..e61b15d 100644
--- a/manifests/upgrade_package.pp
+++ b/manifests/upgrade_package.pp
@@ -1,3 +1,5 @@
+# Install a package either to a certain version, or while making sure that it's
+# always the latest version that's installed.
 define apt::upgrade_package (
   $version = ''
 ) {
@@ -23,7 +25,7 @@ define apt::upgrade_package (
   }
 
   exec { "apt-get -q -y -o 'DPkg::Options::=--force-confold' install ${name}${version_suffix}":
-    onlyif  => [ "grep-status -F Status installed -a -P $name -q", "apt-show-versions -u $name | grep -q upgradeable" ],
+    onlyif  => [ "grep-status -F Status installed -a -P ${name} -q", "apt-show-versions -u ${name} | grep -q upgradeable" ],
     require => Package['apt-show-versions', 'dctrl-tools'],
     before  => Exec['apt_updated']
   }
diff --git a/spec/acceptance/apt_spec.rb b/spec/acceptance/apt_spec.rb
new file mode 100644
index 0000000..a976a56
--- /dev/null
+++ b/spec/acceptance/apt_spec.rb
@@ -0,0 +1,21 @@
+require 'spec_helper_acceptance'
+
+describe 'apt class' do
+
+  context 'default parameters' do
+    it 'should work idempotently with no errors' do
+      pp = <<-EOS
+        class { 'apt': }
+      EOS
+
+      # Run it twice and test for idempotency
+      apply_manifest(pp, :catch_failures => true)
+      apply_manifest(pp, :catch_changes  => true)
+    end
+
+    describe package('apt') do
+      it { is_expected.to be_installed }
+    end
+
+  end
+end
diff --git a/spec/acceptance/nodesets/debian-8-x86_64-docker.yml b/spec/acceptance/nodesets/debian-8-x86_64-docker.yml
new file mode 100644
index 0000000..f09ad62
--- /dev/null
+++ b/spec/acceptance/nodesets/debian-8-x86_64-docker.yml
@@ -0,0 +1,19 @@
+HOSTS:
+  debian-8-x64:
+    platform: debian-8-amd64
+    image: debian:8
+    hypervisor: docker
+    docker_preserve_image: true
+    docker_cmd: '["/sbin/init"]'
+    docker_image_commands:
+      - 'apt-get install -y wget locales-all puppet git'
+      - 'rm -f /usr/sbin/policy-rc.d'
+
+CONFIG:
+  type: foss
+  #log_level: verbose
+  #log_level: debug
+
+ssh:
+  password: root
+  auth_methods: ["password"]
diff --git a/spec/acceptance/nodesets/default.yml b/spec/acceptance/nodesets/default.yml
new file mode 120000
index 0000000..b125a96
--- /dev/null
+++ b/spec/acceptance/nodesets/default.yml
@@ -0,0 +1 @@
+debian-8-x86_64-docker.yml
\ No newline at end of file
diff --git a/spec/spec_helper_acceptance.rb b/spec/spec_helper_acceptance.rb
new file mode 100644
index 0000000..1ccd84d
--- /dev/null
+++ b/spec/spec_helper_acceptance.rb
@@ -0,0 +1,18 @@
+require 'beaker-rspec'
+
+RSpec.configure do |c|
+  module_root = File.expand_path(File.join(File.dirname(__FILE__), '..'))
+  module_name = module_root.split('-').last
+
+  # Readable test descriptions
+  c.formatter = :documentation
+
+  # Configure all nodes in nodeset
+  c.before :suite do
+    # Install module and dependencies
+    puppet_module_install(:source => module_root, :module_name => module_name)
+    hosts.each do |host|
+      shell('git clone https://gitlab.com/shared-puppet-modules-group/common.git /etc/puppet/modules/common')
+    end
+  end
+end