Allow the indexer to be set as a class attribute rather than overriding

app/models/concerns/curation_concerns/file_set/indexing.rb

@@ -3,11 +3,10 @@ module FileSet
     module Indexing
       extend ActiveSupport::Concern
 
-      module ClassMethods
-        # override the default indexing service
-        def indexer
-          CurationConcerns::FileSetIndexer
-        end
+      included do
+        class_attribute :indexer
+        # the default indexing service
+        self.indexer = CurationConcerns::FileSetIndexer
       end
     end
   end

app/models/concerns/curation_concerns/work_behavior.rb

@@ -17,14 +17,11 @@ module CurationConcerns::WorkBehavior
 
   included do
     property :owner, predicate: RDF::URI.new('http://opaquenamespace.org/ns/hydra/owner'), multiple: false
-    class_attribute :human_readable_short_description
+    class_attribute :human_readable_short_description, :indexer
+    self.indexer = CurationConcerns::WorkIndexer
   end
 
   module ClassMethods
-    def indexer
-      CurationConcerns::WorkIndexer
-    end
-
     # This governs which partial to draw when you render this type of object
     def _to_partial_path #:nodoc:
       @_to_partial_path ||= begin

spec/models/curation_concerns/work_behavior_spec.rb

@@ -12,7 +12,7 @@ class EssentialWork < ActiveFedora::Base
 
   subject { EssentialWork.new }
 
-  it 'mixs together all the goodness' do
+  it 'mixes together all the goodness' do
     [::CurationConcerns::WithFileSets, ::CurationConcerns::HumanReadableType, CurationConcerns::Noid, CurationConcerns::Serializers, Hydra::WithDepositor, Hydra::AccessControls::Embargoable, Solrizer::Common].each do |mixin|
       expect(subject.class.ancestors).to include(mixin)
     end
@@ -38,4 +38,12 @@ class EssentialWork < ActiveFedora::Base
     expect(subject.to_solr.keys).to include(:id)
     expect(subject.to_solr.keys).to include('has_model_ssim')
   end
+
+  describe 'indexer' do
+    let(:klass) { Class.new }
+    it 'is settable' do
+      EssentialWork.indexer = klass
+      expect(subject.indexer).to eq klass
+    end
+  end
 end

spec/models/file_set_spec.rb

@@ -148,6 +148,23 @@
   describe '#indexer' do
     subject { described_class.indexer }
     it { is_expected.to eq CurationConcerns::FileSetIndexer }
+
+    describe "setting" do
+      before do
+        class AltFile < ActiveFedora::Base
+          include CurationConcerns::FileSetBehavior
+        end
+      end
+      after do
+        Object.send(:remove_const, :AltFile)
+      end
+      let(:klass) { Class.new }
+      subject { AltFile.new }
+      it 'is settable' do
+        AltFile.indexer = klass
+        expect(subject.indexer).to eq klass
+      end
+    end
   end
 
   it 'supports multi-valued fields in solr' do