diff --git a/spec/system/admin/enterprise_fees_spec.rb b/spec/system/admin/enterprise_fees_spec.rb
index a94c6d5974..a9b5e1b7d5 100644
--- a/spec/system/admin/enterprise_fees_spec.rb
+++ b/spec/system/admin/enterprise_fees_spec.rb
@@ -20,14 +20,11 @@ describe '
     visit spree.edit_admin_general_settings_path
     click_link 'Enterprise Fees'
 
-    expect(page).to have_select "sets_enterprise_fee_set_collection_attributes_0_enterprise_id"
-    expect(page).to have_select "sets_enterprise_fee_set_collection_attributes_0_fee_type",
-                                selected: 'Packing fee'
+    expect(page).to have_select "#{prefix}_enterprise_id"
+    expect(page).to have_select "#{prefix}_fee_type", selected: 'Packing fee'
     expect(page).to have_selector "input[value='$0.50 / kg']"
-    expect(page).to have_select "sets_enterprise_fee_set_collection_attributes_0_tax_category_id",
-                                selected: 'GST'
-    expect(page).to have_select "sets_enterprise_fee_set_collection_attributes_0_calculator_type",
-                                selected: 'Flat Rate (per item)'
+    expect(page).to have_select "#{prefix}_tax_category_id", selected: 'GST'
+    expect(page).to have_select "#{prefix}_calculator_type", selected: 'Flat Rate (per item)'
     expect(page).to have_selector "input[value='#{amount}']"
   end
 
@@ -40,11 +37,11 @@ describe '
     visit admin_enterprise_fees_path
 
     # And I fill in the fields for a new enterprise fee and click update
-    select 'Feedme', from: 'sets_enterprise_fee_set_collection_attributes_0_enterprise_id'
-    select 'Admin', from: 'sets_enterprise_fee_set_collection_attributes_0_fee_type'
-    fill_in 'sets_enterprise_fee_set_collection_attributes_0_name', with: 'Hello!'
-    select 'GST', from: 'sets_enterprise_fee_set_collection_attributes_0_tax_category_id'
-    select 'Flat Percent', from: 'sets_enterprise_fee_set_collection_attributes_0_calculator_type'
+    select 'Feedme', from: "#{prefix}_enterprise_id"
+    select 'Admin', from: "#{prefix}_fee_type"
+    fill_in "#{prefix}_name", with: 'Hello!'
+    select 'GST', from: "#{prefix}_tax_category_id"
+    select 'Flat Percent', from: "#{prefix}_calculator_type"
     click_button 'Update'
 
     # Then I should see my fee and fields for the calculator
@@ -52,12 +49,12 @@ describe '
     expect(page).to have_selector "input[value='Hello!']"
 
     # When I fill in the calculator fields and click update
-    fill_in 'sets_enterprise_fee_set_collection_attributes_0_calculator_attributes'\
-            '_preferred_flat_percent', with: '12.34'
+    fill_in "#{prefix}_calculator_attributes"\
+            "_preferred_flat_percent", with: '12.34'
     click_button 'Update'
 
     # Then I should see the correct values in my calculator fields
-    expect(page).to have_selector("#sets_enterprise_fee_set_collection_attributes_0_calculator"\
+    expect(page).to have_selector("##{prefix}_calculator"\
                                   "_attributes_preferred_flat_percent[value='12.34']")
   end
 
@@ -70,11 +67,11 @@ describe '
     visit admin_enterprise_fees_path
 
     # And I fill in the fields for a new enterprise fee and click update
-    select 'Feedme', from: 'sets_enterprise_fee_set_collection_attributes_0_enterprise_id'
-    select 'Admin', from: 'sets_enterprise_fee_set_collection_attributes_0_fee_type'
-    fill_in 'sets_enterprise_fee_set_collection_attributes_0_name', with: 'Hello!'
-    select 'GST', from: 'sets_enterprise_fee_set_collection_attributes_0_tax_category_id'
-    select 'Flat Percent', from: 'sets_enterprise_fee_set_collection_attributes_0_calculator_type'
+    select 'Feedme', from: "#{prefix}_enterprise_id"
+    select 'Admin', from: "#{prefix}_fee_type"
+    fill_in "#{prefix}_name", with: 'Hello!'
+    select 'GST', from: "#{prefix}_tax_category_id"
+    select 'Flat Percent', from: "#{prefix}_calculator_type"
     click_button 'Update'
 
     # Then I should see my fee and fields for the calculator
@@ -82,10 +79,7 @@ describe '
     expect(page).to have_selector "input[value='Hello!']"
 
     # When I fill in the calculator fields and click update
-    fill_in(
-      'sets_enterprise_fee_set_collection_attributes_0_calculator_attributes_'\
-      'preferred_flat_percent', with: "\'20.0'"
-    )
+    fill_in("#{prefix}_calculator_attributes_preferred_flat_percent", with: "\'20.0'")
     click_button 'Update'
 
     # Then I should see the flash error message
@@ -102,24 +96,21 @@ describe '
       login_as_admin
       visit admin_enterprise_fees_path
       # And I update the fields for the enterprise fee and click update
-      select 'Foo', from: 'sets_enterprise_fee_set_collection_attributes_0_enterprise_id'
-      select 'Admin', from: 'sets_enterprise_fee_set_collection_attributes_0_fee_type'
-      fill_in 'sets_enterprise_fee_set_collection_attributes_0_name', with: 'Greetings!'
+      select 'Foo', from: "#{prefix}_enterprise_id"
+      select 'Admin', from: "#{prefix}_fee_type"
+      fill_in "#{prefix}_name", with: 'Greetings!'
       select 'Inherit From Product', 
-        from: 'sets_enterprise_fee_set_collection_attributes_0_tax_category_id'
-      select 'Flat Percent', from: 'sets_enterprise_fee_set_collection_attributes_0_calculator_type'
+        from: "#{prefix}_tax_category_id"
+      select 'Flat Percent', from: "#{prefix}_calculator_type"
       click_button 'Update'
     end
 
     it "handle the default cases" do
       # Then I should see the updated fields for my fee
-      expect(page).to have_select "sets_enterprise_fee_set_collection_attributes_0_enterprise_id",
-                                  selected: 'Foo'
-      expect(page).to have_select "sets_enterprise_fee_set_collection_attributes_0_fee_type",
-                                  selected: 'Admin fee'
+      expect(page).to have_select "#{prefix}_enterprise_id", selected: 'Foo'
+      expect(page).to have_select "#{prefix}_fee_type", selected: 'Admin fee'
       expect(page).to have_selector "input[value='Greetings!']"
-      expect(page).to have_select 'sets_enterprise_fee_set_collection_attributes_0_tax_category_id',
-                                  selected: 'Inherit From Product'
+      expect(page).to have_select "#{prefix}_tax_category_id", selected: 'Inherit From Product'
       expect(page).to have_selector "option[selected]", text: 'Flat Percent (per item)'
 
       fee.reload
@@ -135,11 +126,11 @@ describe '
 
     it "handle when updating calculator type for Weight to Flat Rate" do
       select 'Weight (per kg or lb)', 
-        from: 'sets_enterprise_fee_set_collection_attributes_0_calculator_type'
+        from: "#{prefix}_calculator_type"
       click_button 'Update'
 
       select 'Flat Rate (per item)', 
-        from: 'sets_enterprise_fee_set_collection_attributes_0_calculator_type'
+        from: "#{prefix}_calculator_type"
       click_button 'Update'
 
       expect(fee.reload.calculator_type).to eq("Calculator::PerItem")
@@ -148,7 +139,7 @@ describe '
     it 'shows error flash when updating fee amount with invalid values' do
       # When I fill in the calculator fields and click update
       fill_in(
-        'sets_enterprise_fee_set_collection_attributes_0_calculator_attributes_'\
+        "#{prefix}_calculator_attributes_"\
         'preferred_flat_percent', with: "\'20.0'"
       )
       click_button 'Update'
@@ -157,6 +148,19 @@ describe '
       expect(flash_message)
         .to eq('Invalid input. Please use only numbers. For example: 10, 5.5, -20')
     end
+
+    it "does not allow editing to an invalid combination" do
+      
+      # starting with a valid tax category / calculator combination
+      expect(page).to have_select "#{prefix}_tax_category_id", selected: 'Inherit From Product'
+      expect(page).to have_selector "option[selected]", text: 'Flat Percent (per item)'
+      
+      # editing to an invalid combination
+      select 'Flat Rate (per order)', 
+        from: "#{prefix}_calculator_type"
+      expect{ click_button 'Update' }.to_not change { fee.reload.calculator_type }
+      expect(page).to have_content "Inheriting the tax categeory requires a per-item calculator."
+    end
   end
 
   it "deleting an enterprise fee" do
@@ -191,28 +195,57 @@ describe '
       login_as enterprise_user
     end
 
-    it "creates enterprise fees" do
-      visit edit_admin_enterprise_path(distributor1)
-      within(".side_menu") { click_link 'Enterprise Fees' }
-      click_link "Create One Now"
+    context "creating an enterprise fee" do
+      before do
+        visit edit_admin_enterprise_path(distributor1)
+        within(".side_menu") { click_link 'Enterprise Fees' }
+        click_link "Create One Now"
+      end
 
-      select distributor1.name,
-             from: 'sets_enterprise_fee_set_collection_attributes_0_enterprise_id'
-      select 'Packing', from: 'sets_enterprise_fee_set_collection_attributes_0_fee_type'
-      fill_in 'sets_enterprise_fee_set_collection_attributes_0_name', with: 'foo'
-      select 'GST', from: 'sets_enterprise_fee_set_collection_attributes_0_tax_category_id'
-      select 'Flat Percent', from: 'sets_enterprise_fee_set_collection_attributes_0_calculator_type'
-      click_button 'Update'
+      shared_examples "setting it up" do |tax_category, calculator, flash_message, fee_count|
+        context "as #{tax_category}, with a #{calculator} calculator" do
+          it "triggers the expected message" do
+            select distributor1.name, from: "#{prefix}_enterprise_id"
+            select 'Packing', from: "#{prefix}_fee_type"
+            fill_in "#{prefix}_name", with: 'foo'
+            select tax_category, from: "#{prefix}_tax_category_id"
+            select calculator, from: "#{prefix}_calculator_type"
+            click_button 'Update'
 
-      expect(flash_message).to eq('Your enterprise fees have been updated.')
+            # The correct flash message should be displayed
+            expect(page).to have_content(flash_message)
 
-      # After saving, we should be redirected to the fees for our chosen enterprise
-      expect(page)
-        .not_to have_select 'sets_enterprise_fee_set_collection_attributes_1_enterprise_id',
-                            selected: 'Second Distributor'
+            # After saving, we should be redirected to the fees for our chosen enterprise
+            expect(page).
+              not_to have_select 'sets_enterprise_fee_set_collection_attributes_1_enterprise_id',
+            selected: 'Second Distributor'
+            
+            # A new enterprise fee is created
+            expect(EnterpriseFee.count).to eq(fee_count)
+          end
+        end
+      end
 
-      enterprise_fee = EnterpriseFee.find_by name: 'foo'
-      expect(enterprise_fee.enterprise).to eq(distributor1)
+      context "an error message is displayed" do
+        message = 'Inheriting the tax categeory requires a per-item calculator.'
+        it_behaves_like "setting it up", 'Inherit From Product',
+                                          'Flat Rate (per order)', message, 0
+      end
+
+      context "an success message is displayed" do
+        message = 'Your enterprise fees have been updated.'
+        it_behaves_like "setting it up", 'Inherit From Product', 'Flat Rate (per item)', message, 1
+      end
+
+      context "an success message is displayed" do
+        message = 'Your enterprise fees have been updated.'
+        it_behaves_like "setting it up", 'GST', 'Flat Rate (per order)', message, 1
+      end
+
+      context "an success message is displayed" do
+        message = 'Your enterprise fees have been updated.'
+        it_behaves_like "setting it up", 'GST', 'Flat Rate (per item)', message, 1
+      end
     end
 
     it "shows me only enterprise fees for the enterprise I select" do
@@ -222,18 +255,15 @@ describe '
       visit edit_admin_enterprise_path(distributor1)
       within(".side_menu") { click_link 'Enterprise Fees' }
       click_link "Manage Enterprise Fees"
-      expect(page).to     have_field 'sets_enterprise_fee_set_collection_attributes_0_name',
-                                     with: 'One'
+      expect(page).to     have_field "#{prefix}_name", with: 'One'
       expect(page).not_to have_field 'sets_enterprise_fee_set_collection_attributes_1_name',
                                      with: 'Two'
 
       visit edit_admin_enterprise_path(distributor2)
       within(".side_menu") { click_link 'Enterprise Fees' }
       click_link "Manage Enterprise Fees"
-      expect(page).not_to have_field 'sets_enterprise_fee_set_collection_attributes_0_name',
-                                     with: 'One'
-      expect(page).to     have_field 'sets_enterprise_fee_set_collection_attributes_0_name',
-                                     with: 'Two'
+      expect(page).not_to have_field "#{prefix}_name", with: 'One'
+      expect(page).to     have_field "#{prefix}_name", with: 'Two'
     end
 
     it "only allows me to select enterprises I have access to" do
@@ -244,9 +274,13 @@ describe '
       visit edit_admin_enterprise_path(distributor2)
       within(".side_menu") { click_link 'Enterprise Fees' }
       click_link "Manage Enterprise Fees"
-      expect(page).to have_select('sets_enterprise_fee_set_collection_attributes_0_enterprise_id',
+      expect(page).to have_select("#{prefix}_enterprise_id",
                                   selected: 'Second Distributor',
                                   options: ['First Distributor', 'Second Distributor'])
     end
   end
 end
+
+def prefix
+  'sets_enterprise_fee_set_collection_attributes_0'
+end