[vcloud|compute] introduce link on a network to parent network

Get the parent network object or nil if no parent network is defined.

lib/fog/vcloud/models/compute/network.rb

@@ -15,6 +15,14 @@ module Fog
 
         attribute :links, :aliases => :Link, :type => :array
 
+        def parent_network
+          return nil if configuration[:ParentNetwork].nil?
+          @parent_network ||= Fog::Vcloud::Compute::Network.new(
+            :connection => connection,
+            :collection => Fog::Vcloud::Compute::Networks.new(:connection => connection),
+            :href => configuration[:ParentNetwork][:href]
+          )
+        end
       end
     end
   end

tests/vcloud/models/compute/network_tests.rb

@@ -37,7 +37,9 @@ Shindo.tests("Vcloud::Compute | network", ['vcloud']) do
       end
     end
     
-    tests("features")
+    tests("#parent_network") do
+      tests("returned network name").returns("ParentNetwork1"){ p = instance.parent_network; p.reload; p.name }
+    end
   end
 
   tests("an external network") do
@@ -56,5 +58,7 @@ Shindo.tests("Vcloud::Compute | network", ['vcloud']) do
       tests("dns").returns("172.0.0.2") { instance.configuration[:IpScope][:Dns1]}
       tests("allocated addresses").returns("172.0.0.144") { instance.configuration[:IpScope][:AllocatedIpAddresses][:IpAddress].first }
     end
+
+    tests("#parent_network").returns(nil){ instance.parent_network }
   end
 end