Add vagrant-based testing environment (DataDog#462)

* Add vagrant-based testing environment

 with '#' will be ignored, and an empty message aborts the commit.

* Update gitignore

* Use versions in Puppetfile

* Fix some paths in the readme

* improve readme

.gitignore

@@ -7,3 +7,5 @@ Gemfile.lock
 
 .rbenv-gemsets
 .ruby-version
+
+tests/.vagrant

tests/README.md

@@ -0,0 +1,38 @@
+# Test setup
+
+This is an example setup, based on vagrant + virtualbox, that allows to easily run puppet commands to test the module.
+
+# Requirements
+
+- vagrant > 2.0.0
+- virtualbox > 5.1.28
+
+# Setup
+
+in `puppet-datadog-agent/tests`:
+
+- provision VM: `vagrant up`
+- connect to the VM to check the configuration: `vagrant ssh`
+- destroy VM when needed: `vagrant destroy -f`
+
+## Module installation
+
+- The default `Puppetfile` installs the latest released version of the module from Puppetforge.
+- To use your development branch instead edit the Puppetfile et replace the `datadog-datadog_agent` with:
+```
+mod 'datadog-datadog_agent',
+  :git    => 'https://github.com/DataDog/puppet-datadog-agent',
+    :branch => '<my_branch>'
+```
+
+- We can also build the module locally using the `puppet build` or `pdk build` command, upload the archive to the VM and install it with `sudo /opt/puppetlabs/bin/puppet module install datadog-datadog_agent-x.y.z.tar.gz --target-dir /home/vagrant/puppet/modules`
+
+
+## Manifest
+
+The default manifest is `tests/environment/manifests/site.pp` and simply run the module with the default options.
+We can edit the manifest and run `vagrant up --provision` to upload the new version to the VM.
+
+# Test
+
+In the VM, run `sudo /opt/puppetlabs/bin/puppet apply --modulepath=./modules ./manifests/site.pp` in `/home/vagrant/puppet` to apply to manifest on the VM.

tests/Vagrantfile

@@ -0,0 +1,10 @@
+Vagrant.configure("2") do |config|
+  config.vm.box = "puppetlabs/ubuntu-16.04-64-puppet"
+  config.vm.box_version = "1.0.0"
+  config.vm.provision "file", source: "./environment", destination: "$HOME/puppet"
+  config.vm.provision "shell", inline: <<-SHELL
+    /opt/puppetlabs/puppet/bin/gem install r10k -v 2.6.4
+    cd /home/vagrant/puppet
+    sudo /opt/puppetlabs/puppet/bin/r10k puppetfile install
+  SHELL
+end

tests/environment/Puppetfile

@@ -0,0 +1,6 @@
+mod 'datadog-datadog_agent'
+mod 'puppetlabs-apt', '2.4.0'
+mod 'puppetlabs-concat', '4.0.0'
+mod 'puppetlabs-puppetserver_gem', '1.0.0'
+mod 'puppetlabs-ruby', '1.0.0'
+mod 'puppetlabs-stdlib', '4.24.0'

tests/environment/manifests/site.pp

@@ -0,0 +1,5 @@
+node "localhost" {
+    class { "datadog_agent":
+       api_key => "somenonnullapikeythats32charlong",
+   }
+}