Update TaxRate transition spec

Setting a tax rate to included fails a validation if a default zone doesn't exist, so that's added. Also improved the tested scenarios and some of the details checked on the updated objects.

spec/controllers/spree/admin/tax_rates_controller_spec.rb

@@ -7,9 +7,10 @@ module Spree
     describe TaxRatesController, type: :controller do
       include AuthenticationHelper
 
+      let!(:default_tax_zone) { create(:zone, default_tax: true) }
       let!(:tax_rate) {
         create(:tax_rate, name: "Original Rate", amount: 0.1, included_in_price: false,
-                          calculator: build(:calculator))
+                          calculator: build(:calculator), zone: default_tax_zone)
       }
 
       describe "#update" do
@@ -34,7 +35,7 @@ module Spree
             end
           end
 
-          context "when the amount or included flag are changed" do
+          context "when the amount is changed" do
             it "duplicates the record and soft-deletes the duplicate" do
               expect {
                 spree_put :update, id: tax_rate.id, tax_rate: { name: "Changed Rate", amount: "0.5" }
@@ -50,6 +51,29 @@ module Spree
               updated_rate = Spree::TaxRate.last
               expect(updated_rate.name).to eq "Changed Rate"
               expect(updated_rate.amount).to eq 0.5
+              expect(updated_rate.deleted?).to be false
+            end
+          end
+
+          context "when included_in_price is changed" do
+            it "duplicates the record and soft-deletes the duplicate" do
+              expect {
+                spree_put :update, id: tax_rate.id, tax_rate: { name: "Changed Rate", included_in_price: "1" }
+              }.to change{ Spree::TaxRate.with_deleted.count }.by(1)
+
+              expect(response).to redirect_to spree.admin_tax_rates_url
+
+              deprecated_rate = tax_rate.reload
+              expect(deprecated_rate.name).to eq "Original Rate"
+              expect(deprecated_rate.amount).to eq 0.1
+              expect(deprecated_rate.included_in_price).to be false
+              expect(deprecated_rate.deleted?).to be true
+
+              updated_rate = Spree::TaxRate.last
+              expect(updated_rate.name).to eq "Changed Rate"
+              expect(updated_rate.amount).to eq 0.1
+              expect(updated_rate.included_in_price).to be true
+              expect(updated_rate.deleted?).to be false
             end
           end
         end