Check property presentation attribute only in test

The PropertySerializer contains :id, :name and :presentation attributes
which leads to JSON objects like `{"id": 1, "name": "foo",
"presentation": "foo"}`. Because of this, we don't care about object
identity, just about their presentation attribute.

spec/serializers/api/cached_enterprise_serializer_spec.rb

@@ -55,15 +55,15 @@ describe Api::CachedEnterpriseSerializer do
 
       it 'does not duplicate properties' do
         properties = cached_enterprise_serializer.distributed_properties
-        expect(properties).to eq([property])
+        expect(properties.map(&:presentation)).to eq([property.presentation])
       end
 
       it 'fetches producer properties' do
         distributed_producer_properties = cached_enterprise_serializer
           .distributed_producer_properties
 
-        expect(distributed_producer_properties)
-          .to eq(producer.producer_properties.map(&:property))
+        expect(distributed_producer_properties.map(&:presentation))
+          .to eq(producer.producer_properties.map(&:property).map(&:presentation))
       end
     end
 
@@ -74,15 +74,15 @@ describe Api::CachedEnterpriseSerializer do
 
       it 'does not duplicate properties' do
         properties = cached_enterprise_serializer.distributed_properties
-        expect(properties).to eq([property])
+        expect(properties.map(&:presentation)).to eq([property.presentation])
       end
 
       it 'fetches producer properties' do
         distributed_producer_properties = cached_enterprise_serializer
           .distributed_producer_properties
 
-        expect(distributed_producer_properties)
-          .to eq(producer.producer_properties.map(&:property))
+        expect(distributed_producer_properties.map(&:presentation))
+          .to eq(producer.producer_properties.map(&:property).map(&:presentation))
       end
     end
   end