diff --git a/spec/netsuite/actions/add_list_spec.rb b/spec/netsuite/actions/add_list_spec.rb
index a6dc65ce7..722361a28 100644
--- a/spec/netsuite/actions/add_list_spec.rb
+++ b/spec/netsuite/actions/add_list_spec.rb
@@ -33,6 +33,19 @@
         expect(response).to be_kind_of(NetSuite::Response)
         expect(response).to be_success
       end
+
+      it 'returns array of records when called as Record static method' do
+        records = NetSuite::Records::Customer.add_list(customers)
+        records.each do |record|
+          expect(record).to be_instance_of(NetSuite::Records::Customer)
+          expect(record.internal_id).not_to be nil
+        end
+      end
+
+      it 'mutates records with internal_id when called as Record static method' do
+        NetSuite::Records::Customer.add_list(customers)
+        expect(customers[0].internal_id).to eq "974"
+      end
     end
 
     context 'two customers' do
@@ -71,6 +84,62 @@
         expect(response).to be_kind_of(NetSuite::Response)
         expect(response).to be_success
       end
+
+      it 'returns array of records when called as Record static method' do
+        records = NetSuite::Records::Customer.add_list(customers)
+        records.each do |record|
+          expect(record).to be_instance_of(NetSuite::Records::Customer)
+          expect(record.internal_id).not_to be nil
+        end
+      end
+
+      it 'mutates records with internal_id when called as Record static method' do
+        NetSuite::Records::Customer.add_list(customers)
+        expect(customers[0].internal_id).to eq "970"
+        expect(customers[1].internal_id).to eq "974"
+      end
+    end
+
+    context 'one customer without external id' do
+      let(:customers) do
+        [
+          NetSuite::Records::Customer.new(entity_id: 'Target', company_name: 'Target')
+        ]
+      end
+
+      before do
+        savon.expects(:add_list).with(:message =>
+          {
+            'record' => [{
+              'listRel:entityId'    => 'Target',
+              'listRel:companyName' => 'Target',
+              '@xsi:type' => 'listRel:Customer'
+            }]
+          }).returns(File.read('spec/support/fixtures/add_list/add_list_one_customer_without_external_id.xml'))
+      end
+
+      it 'makes a valid request to the NetSuite API' do
+        NetSuite::Actions::AddList.call(customers)
+      end
+
+      it 'returns a valid Response object' do
+        response = NetSuite::Actions::AddList.call(customers)
+        expect(response).to be_kind_of(NetSuite::Response)
+        expect(response).to be_success
+      end
+
+      it 'returns array of records when called as Record static method' do
+        records = NetSuite::Records::Customer.add_list(customers)
+        records.each do |record|
+          expect(record).to be_instance_of(NetSuite::Records::Customer)
+          expect(record.internal_id).to be nil
+        end
+      end
+
+      it 'does not mutate records if external_id was not used' do
+        NetSuite::Records::Customer.add_list(customers)
+        expect(customers.first.internal_id).to be nil
+      end
     end
   end