Allow content-id based subscriber lists to match on reverse links

app/queries/subscriber_list_query.rb

@@ -13,7 +13,8 @@ def lists
       lists_matched_on_links +
       lists_matched_on_tags +
       lists_matched_on_document_type_only +
-      lists_matched_on_content_id_only
+      lists_matched_on_content_id_only +
+      lists_with_content_id_matched_on_links
     ).uniq(&:id)
   end
 
@@ -27,6 +28,11 @@ def lists_matched_on_links
     MatchedForNotification.new(query_field: :links, scope: document_type_scope).call(@links)
   end
 
+  def lists_with_content_id_matched_on_links
+    lists_with_content_id = SubscriberList.where.not(content_id: nil)
+    MatchedForNotification.new(query_field: :links, scope: lists_with_content_id).call(@links)
+  end
+
   def lists_matched_on_document_type_only
     FindWithoutLinksAndTags.new(scope: document_type_scope).call
   end

spec/queries/subscriber_list_query_spec.rb

@@ -164,6 +164,41 @@
     end
   end
 
+  context "when list has reverse links" do
+    let(:document_collection_id) { "4d74904a-e45e-47e4-921d-c9dc13c8c9de" }
+    let(:just_another_content_id) { "d876e220-6806-4148-9060-e393d1ff8f3e" }
+    let(:list_params) do
+      { content_id: document_collection_id,
+        links: { document_collections: { any: [document_collection_id] } } }
+    end
+
+    it "includes list where the content id matches, but links do not" do
+      subscriber_list = create_subscriber_list(list_params)
+      query_params = { content_id: document_collection_id, links: {} }
+      query = described_class.new(**content_change_attributes.merge(query_params))
+      expect(query.lists).to include(subscriber_list)
+    end
+
+    it "includes list where links match, but content id does not" do
+      subscriber_list = create_subscriber_list(default_list_attributes.merge(list_params))
+      query_params = {
+        content_id: just_another_content_id,
+        links: { document_collections: [document_collection_id] },
+      }
+      query = described_class.new(**content_change_attributes.merge(query_params))
+
+      expect(query.lists).to include(subscriber_list)
+    end
+
+    it "excludes lists where the content id does not match and links do not match" do
+      subscriber_list = create_subscriber_list(default_list_attributes.merge(list_params))
+      query_params = { content_id: just_another_content_id, links: {} }
+      query = described_class.new(**content_change_attributes.merge(query_params))
+
+      expect(query.lists).not_to include(subscriber_list)
+    end
+  end
+
   def create_subscriber_list(options)
     create(:subscriber_list, options)
   end