Allow search_builder_class to be passed to SearchService

So that this can be set without having to override SearchService

app/controllers/concerns/blacklight/catalog.rb

@@ -163,7 +163,7 @@ def render_sms_action?(_config, _options)
   end
 
   def search_service
-    search_service_class.new(blacklight_config, search_state.to_h)
+    search_service_class.new(blacklight_config, user_params: search_state.to_h)
   end
 
   ##

app/services/blacklight/search_service.rb

@@ -2,16 +2,14 @@
 # SearchService returns search results from the repository
 module Blacklight
   class SearchService
-    def initialize(blacklight_config, user_params = {})
+    def initialize(blacklight_config, user_params: {}, search_builder_class: blacklight_config.search_builder_class)
       @blacklight_config = blacklight_config
       @user_params = user_params
+      @search_builder_class = search_builder_class
     end
 
     # TODO: Can this be private?
-    attr_reader :blacklight_config
-
-    # Override this method to use a search builder other than the one in the config
-    delegate :search_builder_class, to: :blacklight_config
+    attr_reader :blacklight_config, :search_builder_class
 
     def search_builder
       search_builder_class.new(self)

spec/services/blacklight/search_service_spec.rb

@@ -11,7 +11,7 @@
 RSpec.describe Blacklight::SearchService, api: true do
   subject { service }
 
-  let(:service) { described_class.new(blacklight_config, user_params) }
+  let(:service) { described_class.new(blacklight_config, user_params: user_params) }
   let(:repository) { Blacklight::Solr::Repository.new(blacklight_config) }
   let(:user_params) { {} }
 
@@ -29,6 +29,24 @@
     service.repository.connection = blacklight_solr
   end
 
+  describe '#search_builder_class' do
+    subject { service.search_builder_class }
+
+    it 'defaults to the value in the config' do
+      expect(subject).to eq SearchBuilder
+    end
+
+    context 'when the search_builder_class is passed in' do
+      let(:klass) { double("Search builder") }
+
+      let(:service) { described_class.new(blacklight_config, user_params: user_params, search_builder_class: klass) }
+
+      it 'uses the passed value' do
+        expect(subject).to eq klass
+      end
+    end
+  end
+
   # SPECS FOR SEARCH RESULTS FOR QUERY
   describe 'Search Results', integration: true do
     let(:blacklight_config) { copy_of_catalog_config }