diff --git a/app/lib/pre_assembly/digital_object.rb b/app/lib/pre_assembly/digital_object.rb
index 6757aff8c..5fbee9b27 100644
--- a/app/lib/pre_assembly/digital_object.rb
+++ b/app/lib/pre_assembly/digital_object.rb
@@ -72,8 +72,6 @@ def pre_assemble
       log "    - pre_assemble(#{pid}) finished"
     end
 
-    attr_reader :assembly_directory
-
     ####
     # Determining the druid.
     ####
@@ -83,14 +81,15 @@ def druid
       @druid ||= DruidTools::Druid.new(pid)
     end
 
-    def dor_object
-      @dor_object ||= Dor::Item.find(pid)
-    rescue ActiveFedora::ObjectNotFoundError
-      @dor_object = nil
-    end
+    private
+
+    attr_reader :assembly_directory
 
     def content_type_tag
-      dor_object.nil? ? '' : dor_object.content_type_tag
+      dor_object = Dor::Item.find(pid)
+      dor_object.content_type_tag
+    rescue ActiveFedora::ObjectNotFoundError
+      ''
     end
 
     ####
diff --git a/spec/lib/pre_assembly/bundle_spec.rb b/spec/lib/pre_assembly/bundle_spec.rb
index a6d991686..40e6cd053 100644
--- a/spec/lib/pre_assembly/bundle_spec.rb
+++ b/spec/lib/pre_assembly/bundle_spec.rb
@@ -5,58 +5,59 @@
   let(:flat_dir_images) { bundle_setup(:flat_dir_images) }
   let(:images_jp2_tif) { bundle_setup(:images_jp2_tif) }
   let(:multimedia) { bundle_setup(:multimedia) }
-  let(:b) { create(:bundle_context_with_deleted_output_dir).bundle }
+  let(:bundle) { create(:bundle_context_with_deleted_output_dir).bundle }
 
-  after { FileUtils.rm_rf(b.bundle_context.output_dir) if Dir.exist?(b.bundle_context.output_dir) } # cleanup
+  after { FileUtils.rm_rf(bundle.bundle_context.output_dir) if Dir.exist?(bundle.bundle_context.output_dir) } # cleanup
 
   describe '#run_pre_assembly' do
     before do
-      allow(b).to receive(:process_digital_objects) # stub expensive call
-      allow(b).to receive(:log) # log statements we don't care about here
+      allow(bundle).to receive(:process_digital_objects) # stub expensive call
+      allow(bundle).to receive(:log) # log statements we don't care about here
     end
 
     it 'returns processed_pids' do
-      allow(b).to receive(:processed_pids).and_return ['druid:aa111aa1111', 'druid:bb222bb2222']
-      expect(b.run_pre_assembly).to eq ['druid:aa111aa1111', 'druid:bb222bb2222']
+      allow(bundle).to receive(:processed_pids).and_return ['druid:aa111aa1111', 'druid:bb222bb2222']
+      expect(bundle.run_pre_assembly).to eq ['druid:aa111aa1111', 'druid:bb222bb2222']
     end
     it 'logs the start and finish of the run' do
-      expect(b).to receive(:log).with("\nstarting run_pre_assembly(#{b.run_log_msg})")
-      expect(b).to receive(:log).with("\nfinishing run_pre_assembly(#{b.run_log_msg})")
-      b.run_pre_assembly
+      expect(bundle).to receive(:log).with("\nstarting run_pre_assembly(#{bundle.run_log_msg})")
+      expect(bundle).to receive(:log).with("\nfinishing run_pre_assembly(#{bundle.run_log_msg})")
+      bundle.run_pre_assembly
     end
     it 'calls process_digital_objects' do
-      expect(b).to receive(:process_digital_objects)
-      b.run_pre_assembly
+      expect(bundle).to receive(:process_digital_objects)
+      bundle.run_pre_assembly
     end
   end
 
   describe '#process_digital_objects' do
     let(:dor_services_client_object_version) { instance_double(Dor::Services::Client::ObjectVersion, open: true, close: true) }
     let(:dor_services_client_object) { instance_double(Dor::Services::Client::Object, version: dor_services_client_object_version) }
+    let(:item) { instance_double(Dor::Item, content_type_tag: 'image') }
 
     before do
       allow_any_instance_of(PreAssembly::DigitalObject).to receive(:initialize_assembly_workflow)
       allow(Dor::Services::Client).to receive(:object).and_return(dor_services_client_object)
-      allow(Dor::Item).to receive(:find).with(any_args)
+      allow(Dor::Item).to receive(:find).and_return(item)
     end
 
     it 'runs cleanly for new objects' do
       allow_any_instance_of(PreAssembly::DigitalObject).to receive(:'openable?').and_return(false)
       allow_any_instance_of(PreAssembly::DigitalObject).to receive(:current_object_version).and_return(1)
-      expect { b.process_digital_objects }.not_to raise_error
+      expect { bundle.process_digital_objects }.not_to raise_error
     end
 
     it 'runs cleanly for re-accessioned objects that are ready to be versioned' do
       allow_any_instance_of(PreAssembly::DigitalObject).to receive(:'openable?').and_return(true)
       allow_any_instance_of(PreAssembly::DigitalObject).to receive(:current_object_version).and_return(2)
-      expect { b.process_digital_objects }.not_to raise_error
+      expect { bundle.process_digital_objects }.not_to raise_error
     end
 
     it 'throws an exception for re-accessioned objects that are not ready to be versioned' do
       allow_any_instance_of(PreAssembly::DigitalObject).to receive(:'openable?').and_return(false)
       allow_any_instance_of(PreAssembly::DigitalObject).to receive(:current_object_version).and_return(2)
       exp_msg = "druid:aa111aa1111 can't be opened for a new version; cannot re-accession when version > 1 unless object can be opened"
-      expect { b.process_digital_objects }.to raise_error(RuntimeError, exp_msg)
+      expect { bundle.process_digital_objects }.to raise_error(RuntimeError, exp_msg)
     end
   end
 
@@ -92,9 +93,10 @@
   end
 
   describe '#digital_objects' do
+    let(:bundle) { bundle_setup(:folder_manifest) }
+
     it 'finds the correct number of objects' do
-      b = bundle_setup(:folder_manifest)
-      expect(b.digital_objects.size).to eq(3)
+      expect(bundle.digital_objects.size).to eq(3)
     end
 
     it 'handles containers correctly' do
diff --git a/spec/lib/pre_assembly/digital_object_spec.rb b/spec/lib/pre_assembly/digital_object_spec.rb
index 4e9b83a96..73df9ff8b 100644
--- a/spec/lib/pre_assembly/digital_object_spec.rb
+++ b/spec/lib/pre_assembly/digital_object_spec.rb
@@ -84,7 +84,7 @@ def add_object_files(extension = 'tif')
 
     context 'when the copy stager is passed' do
       it 'is able to copy stageable items successfully' do
-        object.stage_files
+        object.send(:stage_files)
         # Check outcome: both source and copy should exist.
         files.each_with_index do |f, i|
           src = object.stageable_items[i]
@@ -100,7 +100,7 @@ def add_object_files(extension = 'tif')
       let(:stager) { PreAssembly::LinkStager }
 
       it 'is able to symlink stageable items successfully' do
-        object.stage_files
+        object.send(:stage_files)
         # Check outcome: both source and copy should exist.
         files.each_with_index do |f, i|
           src = object.stageable_items[i]
@@ -145,30 +145,36 @@ def add_object_files(extension = 'tif')
       END
     end
 
+    let(:assembly_directory) { PreAssembly::AssemblyDirectory.new(druid_id: druid.id) }
+
     before do
       allow(object).to receive(:druid).and_return(druid)
       allow(object).to receive(:content_type_tag).and_return('')
       allow(bc).to receive(:content_structure).and_return('simple_image')
       add_object_files('tif')
       add_object_files('jp2')
+      allow(object).to receive(:assembly_directory).and_return(assembly_directory)
+    end
+
+    around do |example|
+      RSpec::Mocks.with_temporary_scope do
+        Dir.mktmpdir(*tmp_dir_args) do |tmp_area|
+          allow(assembly_directory).to receive(:druid_tree_dir).and_return(tmp_area)
+          example.run
+        end
+      end
     end
 
     it 'generates the expected xml text' do
-      expect(noko_doc(object.create_content_metadata)).to be_equivalent_to exp_xml
+      expect(noko_doc(object.send(:create_content_metadata))).to be_equivalent_to exp_xml
     end
 
     it 'is able to write the content_metadata XML to a file' do
-      assembly_directory = PreAssembly::AssemblyDirectory.new(druid_id: druid.id)
-      allow(object).to receive(:assembly_directory).and_return(assembly_directory)
-
-      Dir.mktmpdir(*tmp_dir_args) do |tmp_area|
-        allow(assembly_directory).to receive(:druid_tree_dir).and_return(tmp_area)
-        assembly_directory.create_object_directories
-        file_name = object.assembly_directory.content_metadata_file
-        expect(File.exist?(file_name)).to eq(false)
-        object.generate_content_metadata
-        expect(noko_doc(File.read(file_name))).to be_equivalent_to exp_xml
-      end
+      assembly_directory.create_object_directories
+      file_name = object.send(:assembly_directory).content_metadata_file
+      expect(File.exist?(file_name)).to eq(false)
+      object.send(:generate_content_metadata)
+      expect(noko_doc(File.read(file_name))).to be_equivalent_to exp_xml
     end
   end
 
@@ -208,7 +214,7 @@ def add_object_files(extension = 'tif')
     end
 
     it 'generates the expected xml text' do
-      expect(noko_doc(object.create_content_metadata)).to be_equivalent_to(exp_xml)
+      expect(noko_doc(object.send(:create_content_metadata))).to be_equivalent_to(exp_xml)
     end
   end
 
@@ -254,7 +260,7 @@ def add_object_files(extension = 'tif')
 
     it 'generates the expected xml text' do
       expect(object.content_md_creation_style).to eq(:file)
-      expect(noko_doc(object.create_content_metadata)).to be_equivalent_to(exp_xml)
+      expect(noko_doc(object.send(:create_content_metadata))).to be_equivalent_to(exp_xml)
     end
   end
 
@@ -269,7 +275,7 @@ def add_object_files(extension = 'tif')
 
     it 'checks if the object is openable' do
       expect(dor_services_client_object_version).to receive(:'openable?')
-      object.openable?
+      object.send(:openable?)
     end
   end
 
@@ -284,7 +290,7 @@ def add_object_files(extension = 'tif')
 
     it 'checks the current object version' do
       expect(dor_services_client_object_version).to receive(:current)
-      object.current_object_version
+      object.send(:current_object_version)
     end
   end
 
@@ -301,12 +307,12 @@ def add_object_files(extension = 'tif')
     it 'opens and closes an object version' do
       expect(dor_services_client_object_version).to receive(:open).with(**version_options)
       expect(dor_services_client_object_version).to receive(:close).with(start_accession: false)
-      object.create_new_version
+      object.send(:create_new_version)
     end
   end
 
   describe '#initialize_assembly_workflow' do
-    subject(:start_workflow) { object.initialize_assembly_workflow }
+    subject(:start_workflow) { object.send(:initialize_assembly_workflow) }
 
     before do
       allow(Dor::Config.workflow).to receive(:client).and_return(client)
diff --git a/spec/lib/pre_assembly/media_spec.rb b/spec/lib/pre_assembly/media_spec.rb
index d0b92c714..35ae9792a 100644
--- a/spec/lib/pre_assembly/media_spec.rb
+++ b/spec/lib/pre_assembly/media_spec.rb
@@ -5,52 +5,55 @@
   let(:bc_params) do
     {
       project_name: 'ProjectBar',
-      # :publish_attr  => { :publish => 'no', :shelve => 'no', :preserve => 'yes' },
       bundle_dir: bundle_dir,
       content_metadata_creation: :media_cm_style
     }
   end
   let(:bc) { build(:bundle_context, bc_params) }
 
-  describe '#create_content_metadata - no thumb declaration' do
-    let(:dobj1) { setup_dobj('aa111aa1111', media_manifest) }
-    let(:dobj2) { setup_dobj('bb222bb2222', media_manifest) }
-    let(:media_manifest) do
-      described_class.new(csv_filename: 'media_manifest.csv', bundle_dir: bundle_dir)
-    end
+  describe '#create_content_metadata' do
+    context 'without thumb declaration' do
+      let(:dobj1) { setup_dobj('aa111aa1111', media_manifest) }
+      let(:dobj2) { setup_dobj('bb222bb2222', media_manifest) }
+      let(:media_manifest) do
+        described_class.new(csv_filename: 'media_manifest.csv', bundle_dir: bundle_dir)
+      end
 
-    it 'generates content metadata from a Media manifest with no thumb columns' do
-      expect(noko_doc(dobj1.create_content_metadata)).to be_equivalent_to noko_doc(exp_xml_object_aa111aa1111)
-      expect(noko_doc(dobj2.create_content_metadata)).to be_equivalent_to noko_doc(exp_xml_object_bb222bb2222)
+      it 'generates content metadata from a Media manifest with no thumb columns' do
+        expect(noko_doc(dobj1.send(:create_content_metadata))).to be_equivalent_to noko_doc(exp_xml_object_aa111aa1111)
+        expect(noko_doc(dobj2.send(:create_content_metadata))).to be_equivalent_to noko_doc(exp_xml_object_bb222bb2222)
+      end
     end
   end
 
-  describe '#create_content_metadata - with thumb declaration' do
-    it 'generates content metadata from a Media manifest with a thumb column set to yes' do
-      media_manifest = described_class.new(csv_filename: 'media_manifest_with_thumb.csv', bundle_dir: bundle_dir)
-      dobj1 = setup_dobj('aa111aa1111', media_manifest)
-      dobj2 = setup_dobj('bb222bb2222', media_manifest)
+  describe '#create_content_metadata' do
+    context 'with thumb declaration' do
+      it 'generates content metadata from a Media manifest with a thumb column set to yes' do
+        media_manifest = described_class.new(csv_filename: 'media_manifest_with_thumb.csv', bundle_dir: bundle_dir)
+        dobj1 = setup_dobj('aa111aa1111', media_manifest)
+        dobj2 = setup_dobj('bb222bb2222', media_manifest)
 
-      expect(noko_doc(dobj1.create_content_metadata)).to be_equivalent_to noko_doc(exp_xml_object_aa111aa1111_with_thumb)
-      expect(noko_doc(dobj2.create_content_metadata)).to be_equivalent_to noko_doc(exp_xml_object_bb222bb2222)
-    end
+        expect(noko_doc(dobj1.send(:create_content_metadata))).to be_equivalent_to noko_doc(exp_xml_object_aa111aa1111_with_thumb)
+        expect(noko_doc(dobj2.send(:create_content_metadata))).to be_equivalent_to noko_doc(exp_xml_object_bb222bb2222)
+      end
 
-    it 'generates content metadata from a Media manifest with a thumb column set to true' do
-      media_manifest = described_class.new(csv_filename: 'media_manifest_with_thumb_true.csv', bundle_dir: bundle_dir)
-      dobj1 = setup_dobj('aa111aa1111', media_manifest)
-      dobj2 = setup_dobj('bb222bb2222', media_manifest)
+      it 'generates content metadata from a Media manifest with a thumb column set to true' do
+        media_manifest = described_class.new(csv_filename: 'media_manifest_with_thumb_true.csv', bundle_dir: bundle_dir)
+        dobj1 = setup_dobj('aa111aa1111', media_manifest)
+        dobj2 = setup_dobj('bb222bb2222', media_manifest)
 
-      expect(noko_doc(dobj1.create_content_metadata)).to be_equivalent_to noko_doc(exp_xml_object_aa111aa1111_with_thumb)
-      expect(noko_doc(dobj2.create_content_metadata)).to be_equivalent_to noko_doc(exp_xml_object_bb222bb2222)
-    end
+        expect(noko_doc(dobj1.send(:create_content_metadata))).to be_equivalent_to noko_doc(exp_xml_object_aa111aa1111_with_thumb)
+        expect(noko_doc(dobj2.send(:create_content_metadata))).to be_equivalent_to noko_doc(exp_xml_object_bb222bb2222)
+      end
 
-    it 'generates content metadata from a Media manifest with no thumbs when the thumb column is set to no' do
-      media_manifest = described_class.new(csv_filename: 'media_manifest_thumb_no.csv', bundle_dir: bundle_dir)
-      dobj1 = setup_dobj('aa111aa1111', media_manifest)
-      dobj2 = setup_dobj('bb222bb2222', media_manifest)
+      it 'generates content metadata from a Media manifest with no thumbs when the thumb column is set to no' do
+        media_manifest = described_class.new(csv_filename: 'media_manifest_thumb_no.csv', bundle_dir: bundle_dir)
+        dobj1 = setup_dobj('aa111aa1111', media_manifest)
+        dobj2 = setup_dobj('bb222bb2222', media_manifest)
 
-      expect(noko_doc(dobj1.create_content_metadata)).to be_equivalent_to noko_doc(exp_xml_object_aa111aa1111)
-      expect(noko_doc(dobj2.create_content_metadata)).to be_equivalent_to noko_doc(exp_xml_object_bb222bb2222)
+        expect(noko_doc(dobj1.send(:create_content_metadata))).to be_equivalent_to noko_doc(exp_xml_object_aa111aa1111)
+        expect(noko_doc(dobj2.send(:create_content_metadata))).to be_equivalent_to noko_doc(exp_xml_object_bb222bb2222)
+      end
     end
   end