Per review, clean up voucher specs

Add explicit 'order.item_total' to make specs more readable

spec/factories/voucher_factory.rb

@@ -2,6 +2,7 @@
 
 FactoryBot.define do
   factory :voucher, class: Voucher do
+    code { "new_code" }
     enterprise { build(:distributor_enterprise) }
     amount { 10 }
   end

spec/models/vouchers/flat_rate_spec.rb

@@ -3,10 +3,8 @@
 require 'spec_helper'
 
 describe Vouchers::FlatRate do
-  let(:enterprise) { build(:enterprise) }
-
   describe 'validations' do
-    subject { build(:voucher_flat_rate, code: 'new_code', enterprise:) }
+    subject { build(:voucher_flat_rate) }
 
     it { is_expected.to validate_presence_of(:amount) }
     it { is_expected.to validate_numericality_of(:amount).is_greater_than(0) }
@@ -15,29 +13,37 @@
   describe '#compute_amount' do
     let(:order) { create(:order_with_totals) }
 
+    before do
+      order.update_columns(item_total: 15)
+    end
+
     context 'when order total is more than the voucher' do
-      subject { create(:voucher_flat_rate, code: 'new_code', enterprise:, amount: 5) }
+      subject { create(:voucher_flat_rate, amount: 5) }
 
       it 'uses the voucher total' do
         expect(subject.compute_amount(order).to_f).to eq(-5)
       end
     end
 
     context 'when order total is less than the voucher' do
-      subject { create(:voucher_flat_rate, code: 'new_code', enterprise:, amount: 20) }
+      subject { create(:voucher_flat_rate, amount: 20) }
 
       it 'matches the order total' do
-        expect(subject.compute_amount(order).to_f).to eq(-10)
+        expect(subject.compute_amount(order).to_f).to eq(-15)
       end
     end
   end
 
   describe "#rate" do
     subject do
-      create(:voucher_flat_rate, code: 'new_code', enterprise:, amount: 5)
+      create(:voucher_flat_rate, code: 'new_code', amount: 5)
     end
     let(:order) { create(:order_with_totals) }
 
+    before do
+      order.update_columns(item_total: 10)
+    end
+
     it "returns the voucher rate" do
       # rate = -voucher_amount / order.pre_discount_total
       # -5 / 10 = -0.5

spec/models/vouchers/percentage_rate_spec.rb

@@ -3,10 +3,8 @@
 require 'spec_helper'
 
 describe Vouchers::PercentageRate do
-  let(:enterprise) { build(:enterprise) }
-
   describe 'validations' do
-    subject { build(:voucher_percentage_rate, code: 'new_code', enterprise:) }
+    subject { build(:voucher_percentage_rate) }
 
     it { is_expected.to validate_presence_of(:amount) }
     it do
@@ -18,18 +16,22 @@
 
   describe '#compute_amount' do
     subject do
-      create(:voucher_percentage_rate, code: 'new_code', enterprise:, amount: 10)
+      create(:voucher_percentage_rate, amount: 10)
     end
     let(:order) { create(:order_with_totals) }
 
+    before do
+      order.update_columns(item_total: 15)
+    end
+
     it 'returns percentage of the order total' do
-      expect(subject.compute_amount(order)).to eq(-order.pre_discount_total * 0.1)
+      expect(subject.compute_amount(order)).to eq(-1.5)
     end
   end
 
   describe "#rate" do
     subject do
-      create(:voucher_percentage_rate, code: 'new_code', enterprise:, amount: 50)
+      create(:voucher_percentage_rate, amount: 50)
     end
 
     it "returns the voucher percentage rate" do