Added check for repository being called with Search Builder

Knowing that this stuff is fiddley I just played with it a bit to get a working version.  No intention of leaving the Ensemble out just wanted to get the syntax correct.

spec/controllers/catalog_controller_spec.rb

@@ -128,11 +128,12 @@
           # We want to make sure that the repository (in
           # controller.blacklight_config.repository) receives search with an
           # instance of SearchBuilder.
-          allow(AlternateSearchBuilder).to receive(:new).and_call_original
-
+          repository = CatalogController.blacklight_config.repository
+          allow(repository).to receive(:search).and_call_original
+          allow_any_instance_of(Blacklight::Configuration).to receive(:repository).and_return(repository)
           get :index, params: { q: "coffee" }
 
-          expect(AlternateSearchBuilder).not_to have_received(:new)
+          expect(repository).to have_received(:search).with(instance_of(SearchBuilder))
         end
       end