Add auth_file acceptance test

This commit adds boilerplate code for beaker-rspec acceptance tests and
an acceptance test for the auth_file class.

Change-Id: Ibfcc66212d41e98e785776f6450c32d12d3a6e1f

spec/acceptance/openstack_extras_auth_file_spec.rb

@@ -0,0 +1,24 @@
+require 'spec_helper_acceptance'
+
+describe 'openstack_extras::auth_file' do
+
+  context 'default parameters' do
+
+    it 'should work with no errors' do
+      pp= <<-EOS
+        class { '::openstack_extras::auth_file':
+          password => 'secret',
+        }
+      EOS
+
+
+      # Run it twice and test for idempotency
+      apply_manifest(pp, :catch_failures => true)
+      apply_manifest(pp, :catch_changes => true)
+    end
+
+    describe file('/root/openrc') do
+      it  { is_expected.to be_file }
+    end
+  end
+end