Spec fix for parameters

- Use it_behaves_like 'an idempotent resource' in parameter_spec
- Hacky spec test fix for lack of idempotency when installing implicitly
  enabled plugins with newer RabbitMQ versions (see voxpupuli#844)

Author: wyardley

spec/acceptance/parameter_spec.rb

@@ -5,39 +5,40 @@
 describe 'rabbitmq parameter on a vhost:' do
   context 'create parameter resource' do
     it 'runs successfully' do
-      pp = <<-EOS
-      if $facts['os']['family'] == 'RedHat' {
-        class { 'erlang': epel_enable => true }
-        Class['erlang'] -> Class['rabbitmq']
-      }
-      class { 'rabbitmq':
-        service_manage    => true,
-        port              => 5672,
-        delete_guest_user => true,
-        admin_enable      => true,
-      }
+      let(:pp) do
+        <<-EOS
+        if $facts['os']['family'] == 'RedHat' {
+          class { 'erlang': epel_enable => true }
+          Class['erlang'] -> Class['rabbitmq']
+        }
+        class { 'rabbitmq':
+          service_manage    => true,
+          port              => 5672,
+          delete_guest_user => true,
+          admin_enable      => true,
+        }
 
-      rabbitmq_plugin { [ 'rabbitmq_federation_management', 'rabbitmq_federation' ]:
-        ensure => present
-      } ~> Service['rabbitmq-server']
+        rabbitmq_plugin { [ 'rabbitmq_federation_management' ]:
+          ensure => present
+        } ~> Service['rabbitmq-server']
 
-      rabbitmq_vhost { 'fedhost':
-        ensure => present,
-      } ->
+        rabbitmq_vhost { 'fedhost':
+          ensure => present,
+        } ->
 
-      rabbitmq_parameter { 'documentumFed@fedhost':
-        component_name => 'federation-upstream',
-        value          => {
-          'uri'    => 'amqp://server',
-          'expires' => '3600000',
-        },
-      }
-      EOS
-
-      apply_manifest(pp, catch_failures: true)
-      apply_manifest(pp, catch_changes: true)
+        rabbitmq_parameter { 'documentumFed@fedhost':
+          component_name => 'federation-upstream',
+          value          => {
+            'uri'    => 'amqp://server',
+            'expires' => '3600000',
+          },
+        }
+        EOS
+      end
     end
 
+    it_behaves_like 'an idempotent resource'
+
     it 'has the parameter' do
       shell('rabbitmqctl list_parameters -p fedhost') do |r|
         expect(r.stdout).to match(%r{federation-upstream.*documentumFed.*expires.*3600000})