make it optional whether to include blank values in linked data exten…

…ded context

app/models/qa/linked_data/config/context_property_map.rb

@@ -37,6 +37,7 @@ def initialize(property_map = {}, prefixes = {})
           @ldpath = Qa::LinkedData::Config::Helper.fetch_required(property_map, :ldpath, false)
           @selectable = Qa::LinkedData::Config::Helper.fetch_boolean(property_map, :selectable, false)
           @drillable = Qa::LinkedData::Config::Helper.fetch_boolean(property_map, :drillable, false)
+          @optional = Qa::LinkedData::Config::Helper.fetch_boolean(property_map, :optional, false)
           @expansion_label_ldpath = Qa::LinkedData::Config::Helper.fetch(property_map, :expansion_label_ldpath, nil)
           @expansion_id_ldpath = Qa::LinkedData::Config::Helper.fetch(property_map, :expansion_id_ldpath, nil)
           @prefixes = prefixes
@@ -54,6 +55,12 @@ def drillable?
           @drillable
         end
 
+        # Should this property always be included in the extended context or is it optional (i.e. only shown if it has a value)
+        # @return [Boolean] true if this property is optional and will only be included in extended context if it has a value; otherwise, false
+        def optional?
+          @optional
+        end
+
         def group?
           group_id.present?
         end

app/services/qa/linked_data/mapper/context_mapper_service.rb

@@ -37,7 +37,11 @@ def populate_property_map(context_map, property_map, graph, subject_uri)
                 values = Qa::LinkedData::Config::ContextPropertyMap::VALUE_ON_ERROR
                 error = e.message
               end
+              return {} if values.blank? && property_map.optional?
+              property_info(values, error, context_map, property_map)
+            end
 
+            def property_info(values, error, context_map, property_map)
               property_info = {}
               property_info["group"] = context_map.group_label(property_map.group_id) if property_map.group?
               property_info["property"] = property_map.label

spec/services/linked_data/mapper/context_mapper_service_spec.rb

@@ -7,17 +7,19 @@
   let(:context_map) { instance_double(Qa::LinkedData::Config::ContextMap) }
   let(:subject_uri) { instance_double(RDF::URI) }
 
-  let(:context_properties) { [birth_date_property_map, death_date_property_map, occupation_property_map] }
+  let(:context_properties) { [birth_date_property_map, death_date_property_map, occupation_property_map, missing_property_map] }
 
   let(:birth_date_property_map) { instance_double(Qa::LinkedData::Config::ContextPropertyMap) }
   let(:death_date_property_map) { instance_double(Qa::LinkedData::Config::ContextPropertyMap) }
   let(:occupation_property_map) { instance_double(Qa::LinkedData::Config::ContextPropertyMap) }
+  let(:missing_property_map)    { instance_double(Qa::LinkedData::Config::ContextPropertyMap) }
 
   let(:group_id) { 'dates' }
 
   let(:birth_date_values) { ['10/15/1943'] }
   let(:death_date_values) { ['12/17/2018'] }
   let(:occupation_values) { ['Actress', 'Director', 'Producer'] }
+  let(:missing_values) { [] }
 
   before do
     allow(context_map).to receive(:properties).and_return(context_properties)
@@ -29,20 +31,31 @@
     allow(birth_date_property_map).to receive(:selectable?).and_return(false)
     allow(birth_date_property_map).to receive(:drillable?).and_return(false)
     allow(birth_date_property_map).to receive(:expand_uri?).and_return(false)
+    allow(birth_date_property_map).to receive(:optional?).and_return(false)
 
     allow(death_date_property_map).to receive(:label).and_return('Death')
     allow(death_date_property_map).to receive(:values).with(graph, subject_uri).and_return(death_date_values)
     allow(death_date_property_map).to receive(:group?).and_return(false)
     allow(death_date_property_map).to receive(:selectable?).and_return(false)
     allow(death_date_property_map).to receive(:drillable?).and_return(false)
     allow(death_date_property_map).to receive(:expand_uri?).and_return(false)
+    allow(death_date_property_map).to receive(:optional?).and_return(false)
 
     allow(occupation_property_map).to receive(:label).and_return('Occupation')
     allow(occupation_property_map).to receive(:values).with(graph, subject_uri).and_return(occupation_values)
     allow(occupation_property_map).to receive(:group?).and_return(false)
     allow(occupation_property_map).to receive(:selectable?).and_return(false)
     allow(occupation_property_map).to receive(:drillable?).and_return(false)
     allow(occupation_property_map).to receive(:expand_uri?).and_return(false)
+    allow(occupation_property_map).to receive(:optional?).and_return(false)
+
+    allow(missing_property_map).to receive(:label).and_return('Property with NO values')
+    allow(missing_property_map).to receive(:values).with(graph, subject_uri).and_return(missing_values)
+    allow(missing_property_map).to receive(:group?).and_return(false)
+    allow(missing_property_map).to receive(:selectable?).and_return(false)
+    allow(missing_property_map).to receive(:drillable?).and_return(false)
+    allow(missing_property_map).to receive(:expand_uri?).and_return(false)
+    allow(missing_property_map).to receive(:optional?).and_return(true)
   end
 
   describe '.map_context' do
@@ -115,6 +128,21 @@
       end
     end
 
+    context 'when optional? is false' do
+      before { allow(missing_property_map).to receive(:optional?).and_return(false) }
+      it 'includes property with blank values' do
+        result = find_property_to_test(subject, 'Property with NO values')
+        expect(result['values']).to eq []
+      end
+    end
+
+    context 'when optional? is true' do
+      before { allow(missing_property_map).to receive(:optional?).and_return(true) }
+      it 'property with blank values is not added to results' do
+        expect { find_property_to_test(subject, 'Property with NO values') }.to raise_error StandardError, "property 'Property with NO values' not found"
+      end
+    end
+
     context 'when error occurs' do
       let(:cause) { I18n.t('qa.linked_data.ldpath.parse_error') }
       before { allow(occupation_property_map).to receive(:values).with(graph, subject_uri).and_raise(cause) }
@@ -132,6 +160,6 @@ def find_property_to_test(results, label)
       next unless r['property'] == label
       return r
     end
-    raise "property (#{label}) to test not found"
+    raise StandardError, "property '#{label}' not found"
   end
 end