init thumbnail presenter tests

spec/presenters/blacklight/thumbnail_presenter_spec.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+require 'rails_helper'
+require Rails.root.join('app/overrides/presenters/blacklight/thumbnail_presenter_override.rb')
+
+RSpec.describe Blacklight::ThumbnailPresenter do
+  describe '#retrieve_values' do
+    it 'does not attempt to process a solr document if it is nil' do
+      # Mock field config and view context
+      field_config = double('FieldConfig')
+      view_context = double('ViewContext')
+      presenter = Blacklight::ThumbnailPresenter.new(nil, view_context, field_config)
+
+      retriever_instance = Blacklight::FieldRetriever.new(nil, nil, nil)
+      allow(Blacklight::FieldRetriever).to receive(:new).and_return(retriever_instance)
+      allow(retriever_instance).to receive(:fetch).and_return('default_thumbnail')
+      allow(presenter).to receive(:extract_solr_document)
+
+      presenter.send(:retrieve_values, field_config)
+      expect(Blacklight::FieldRetriever).to have_received(:new).with(nil, field_config, view_context)
+      # Presenter should not process the document if it's nil
+      expect(presenter).not_to have_received(:extract_solr_document)
+    end
+  end
+end