rake_tasks: support Puppetfile_extras

In the case of puppet-tripleo, we would like to re-use
puppet-openstack_spec_helper/rake_tasks but we have more Puppet modules
than Puppet OpenStack, and some of them are third party (not supported
by any community).

So we would like to create a Puppetfile_extras with the modules specific to
TripleO and re-use Puppetfile from Puppet OpenStack.
This patch will merge the 2 Puppetfiles if Puppetfile_extras does exist in one
Puppet module.

Change-Id: I337fb246f326510a3bd459f777dc6a353f9d6924

lib/puppet-openstack_spec_helper/rake_tasks.rb

@@ -61,6 +61,11 @@ task :spec_prep do
     else
       sh("git clone https://git.openstack.org/#{repo} #{repo}")
     end
+    # Allow to a repository to have extra modules that are not
+    # in puppet-openstack-integration
+    if File.exists?("#{Dir.pwd}/Puppetfile_extras")
+      sh("cat #{Dir.pwd}/Puppetfile_extras >> #{repo}/Puppetfile")
+    end
     script = ['env']
     script += ["PUPPETFILE_DIR=#{Dir.pwd}/spec/fixtures/modules"]
     script += ["ZUUL_REF=#{zuul_ref}"]

releasenotes/notes/puppetfile_extras-f49799b6edbe69a2.yaml

@@ -0,0 +1,6 @@
+---
+features:
+  - If Puppetfile_extras file does exist in a Puppet module, the spec_helper will copy
+    its content to the end of Puppet OpenStack Puppetfile. It will allow external modules
+    (for example puppet-tripleo) to re-use Puppet OpenStack tooling, but adding more modules
+    in the tests.