Limit number of subjects displayed on index page

app/controllers/catalog_controller.rb

@@ -51,7 +51,7 @@ def self.search_config
     #   The ordering of the field names is the order of the display
     config.add_index_field solr_name('description', :stored_searchable)
     config.add_index_field solr_name('tag', :stored_searchable)
-    config.add_index_field solr_name('subject', :stored_searchable)
+    config.add_index_field solr_name('subject', :stored_searchable), helper_method: :index_subject
     config.add_index_field solr_name('creator', :stored_searchable)
     config.add_index_field solr_name('contributor', :stored_searchable)
     config.add_index_field solr_name('publisher', :stored_searchable)

app/helpers/index_view_helper.rb

@@ -0,0 +1,7 @@
+module IndexViewHelper
+  # Limit the number of subjects displayed on index page.
+  # Mainly because of geo works.
+  def index_subject(args)
+    args[:document].subject.take(7).join("<br/>")
+  end
+end

spec/helpers/index_view_helper_spec.rb

@@ -0,0 +1,16 @@
+require 'rails_helper'
+
+describe IndexViewHelper do
+  subject { helper }
+  let(:document) { instance_double(SolrDocument, subject: subject_list) }
+  let(:args) { { document: document } }
+
+  describe '#index_subject' do
+    context 'with a long list of subject terms' do
+      let(:subject_list) { ['1', '2', '3', '4', '5', '6', '7', '8', '9'] }
+      it 'returns a list with a maximum of 7 items' do
+        expect(subject.index_subject(args)).to eq '1<br/>2<br/>3<br/>4<br/>5<br/>6<br/>7'
+      end
+    end
+  end
+end