Improve rabbitmq type acceptance tests

This patch adds checks for idempotency and improves the shell command
syntax to contain one test at a time and use rspec tools to check
output and exit codes.

spec/acceptance/policy_spec.rb

@@ -33,13 +33,14 @@ class { '::rabbitmq':
       EOS
 
       apply_manifest(pp, :catch_failures => true)
+      apply_manifest(pp, :catch_changes => true)
     end
 
-    describe command('rabbitmqctl list_policies -p myhost') do
-      its(:stdout) { should match /myhost/ }
-      its(:stdout) { should match /ha-all/ }
-      its(:stdout) { should match /ha-sync-mode/ }
-      its(:stdout) { should match /\.\*/ }
+    it 'should have the policy' do
+      shell('rabbitmqctl list_policies -p myhost') do |r|
+        expect(r.stdout).to match(/myhost.*ha-all.*ha-sync-mode/)
+        expect(r.exit_code).to be_zero
+      end
     end
 
   end

spec/acceptance/user_spec.rb

@@ -24,11 +24,14 @@ class { '::rabbitmq':
       EOS
 
       apply_manifest(pp, :catch_failures => true)
+      apply_manifest(pp, :catch_changes => true)
     end
 
-    describe command('rabbitmqctl list_users | grep dan') do
-      its(:stdout) { should match /dan/ }
-      its(:stdout) { should match /administrator/ }
+    it 'should have the user' do
+      shell('rabbitmqctl list_users') do |r|
+        expect(r.stdout).to match(/dan.*administrator/)
+        expect(r.exit_code).to be_zero
+      end
     end
 
   end

spec/acceptance/vhost_spec.rb

@@ -23,10 +23,14 @@ class { '::rabbitmq':
       EOS
 
       apply_manifest(pp, :catch_failures => true)
+      apply_manifest(pp, :catch_changes => true)
     end
 
-    describe command('rabbitmqctl list_vhosts | grep myhost') do
-      its(:stdout) { should match /myhost/ }
+    it 'should have the vhost' do
+      shell('rabbitmqctl list_vhosts') do |r|
+        expect(r.stdout).to match(/myhost/)
+        expect(r.exit_code).to be_zero
+      end
     end
 
   end