Add thumbnails to index view.

app/helpers/thumbnail_helper.rb

@@ -0,0 +1,8 @@
+module ThumbnailHelper
+  include Blacklight::CatalogHelper
+  # Had to override the thumbnail URL because the document doesn't directly have
+  # the relative URL, just the raw location of the thumbnail on disk.
+  def thumbnail_url document
+    document.derivative_paths[:thumbnail].relative_path.to_s
+  end
+end

app/models/blacklight_config.rb

@@ -23,7 +23,8 @@ def configurations
       ViewConfiguration.new(configuration),
       DefaultConfiguration.new(configuration),
       SearchFieldConfiguration.new(configuration),
-      ShowActions.new(configuration)
+      ShowActions.new(configuration),
+      ThumbnailConfiguration.new(configuration)
     ]
   end
 

app/models/blacklight_config/thumbnail_configuration.rb

@@ -0,0 +1,6 @@
+class BlacklightConfig::ThumbnailConfiguration
+  pattr_initialize :configuration
+  def run
+    configuration.index.thumbnail_field = :workflow_metadata__thumbnail_path_ssim
+  end
+end

spec/views/catalog/_thumbnail_default.html.erb_spec.rb

@@ -0,0 +1,29 @@
+require 'rails_helper'
+
+RSpec.describe "catalog/_thumbnail_default.html.erb" do
+  let(:document) { SolrDocument.new(solr_hash) }
+  let(:solr_hash) {
+    {
+      :id => "1",
+      :workflow_metadata__thumbnail_path_ssim => [OregonDigital.derivative_injector.thumbnail_path("13")]
+    }
+  }
+  let(:blacklight_config) {
+    BlacklightConfig.new(GenericAsset, CatalogController.blacklight_config).configuration
+  }
+  describe "thumbnails" do
+    before do
+      allow(view).to receive(:blacklight_config).and_return(blacklight_config)
+      allow(view).to receive(:render_grouped_response?).and_return false
+      allow(view).to receive(:current_search_session).and_return nil
+      allow(view).to receive(:search_session).and_return({})
+      assign :response, double(start: 0)
+      render :partial => "catalog/thumbnail_default", :locals => {:document => document, :document_counter => 1}
+    end
+    context "when there's a thumbnail" do
+      it "should show it" do
+        expect(rendered).to have_selector "img[src='/media/thumbnails/3/1/13.jpg']"
+      end
+    end
+  end
+end