dashboard: more puppetish syntax

manifests/dashboard.pp

@@ -70,8 +70,7 @@ class cloud::dashboard(
   $debug                     = $os_params::debug
 ) {
 
-  $supported = [ 'RedHat', 'Debian' ]
-  if grep($supported, $::osfamily) != [$::osfamily] {
+  if ! ($::osfamily in [ 'RedHat', 'Debian' ]) {
     fail("module puppet-horizon doesn't support ${::osfamily}")
   }
 

spec/classes/cloud_dashboard_spec.rb

@@ -71,4 +71,16 @@ describe 'cloud::dashboard' do
     it_configures 'openstack dashboard'
   end
 
+  context 'on other platforms' do
+    let :facts do
+      { :osfamily => 'Solaris',
+        :operatingsystemrelease => '10',
+        :concat_basedir         => '/var/lib/puppet/concat' }
+    end
+
+    it 'should fail' do
+      expect { subject }.to  raise_error(/module puppet-horizon doesn't support/)
+    end
+  end
+
 end