Allow creating custom vat rates

ecommerce/taxes/lib/taxes/commands.rb

@@ -1,7 +1,7 @@
 module Taxes
   class SetVatRate < Infra::Command
     attribute :product_id, Infra::Types::UUID
-    attribute :vat_rate, Infra::Types::VatRate
+    attribute :vat_rate_code, Infra::Types::String
   end
 
   class DetermineVatRate < Infra::Command

ecommerce/taxes/lib/taxes/product.rb

@@ -2,23 +2,16 @@ module Taxes
   class Product
     include AggregateRoot
 
-    VatRateNotApplicable = Class.new(StandardError)
-
     def initialize(id)
       @id = id
     end
 
-    def set_vat_rate(vat_rate, catalog)
-      raise VatRateNotApplicable unless vat_rate_applicable?(vat_rate.code, catalog)
+    def set_vat_rate(vat_rate)
       apply(VatRateSet.new(data: { product_id: @id, vat_rate: vat_rate }))
     end
 
     private
 
-    def vat_rate_applicable?(vat_rate_code, catalog)
-      catalog.vat_rate_available?(vat_rate_code)
-    end
-
     on(VatRateSet) { |_| }
   end
 end

ecommerce/taxes/lib/taxes/services.rb

@@ -1,14 +1,17 @@
 module Taxes
   VatRateAlreadyExists = Class.new(StandardError)
+  VatRateNotApplicable = Class.new(StandardError)
   class SetVatRateHandler
     def initialize(event_store)
       @repository = Infra::AggregateRootRepository.new(event_store)
       @catalog = VatRateCatalog.new(event_store)
     end
 
     def call(cmd)
+      vat_rate = @catalog.vat_rate_by_code(cmd.vat_rate_code)
+      raise VatRateNotApplicable unless vat_rate
       @repository.with_aggregate(Product, cmd.product_id) do |product|
-        product.set_vat_rate(cmd.vat_rate, @catalog)
+        product.set_vat_rate(vat_rate)
       end
     end
   end
@@ -44,7 +47,7 @@ def initialize(event_store)
     end
 
     def call(cmd)
-      raise VatRateAlreadyExists if catalog.vat_rate_available?(cmd.vat_rate.code)
+      raise VatRateAlreadyExists if catalog.vat_rate_by_code(cmd.vat_rate.code)
 
       event_store.publish(available_vat_rate_added_event(cmd), stream_name: stream_name(cmd))
     end

ecommerce/taxes/lib/taxes/vat_rate_catalog.rb

@@ -15,12 +15,14 @@ def vat_rate_for(product_id)
         &.fetch(:vat_rate)
     end
 
-    def vat_rate_available?(vat_rate_code)
+    def vat_rate_by_code(vat_rate_code)
       @event_store
         .read
         .stream("Taxes::AvailableVatRate$#{vat_rate_code}")
-        .to_a
-        .any?
+        .last
+        &.data
+        &.fetch(:vat_rate)
+        &.then { |vat_rate| Infra::Types::VatRate.new(vat_rate) }
     end
   end
 end

ecommerce/taxes/test/taxes_test.rb

@@ -9,16 +9,16 @@ def test_setting_available_vat_rate
       product_id = SecureRandom.uuid
       vat_rate_set = VatRateSet.new(data: { product_id: product_id, vat_rate: vat_rate })
       assert_events("Taxes::Product$#{product_id}", vat_rate_set) do
-        set_vat_rate(product_id, vat_rate)
+        set_vat_rate(product_id, vat_rate.code)
       end
     end
 
     def test_setting_unavailable_vat_rate_should_raise_error
       product_id = SecureRandom.uuid
       unavailable_vat_rate = Infra::Types::VatRate.new(code: "20", rate: 20)
 
-      assert_raises(Product::VatRateNotApplicable) do
-        set_vat_rate(product_id, unavailable_vat_rate)
+      assert_raises(Taxes::VatRateNotApplicable) do
+        set_vat_rate(product_id, unavailable_vat_rate.code)
       end
     end
 
@@ -30,7 +30,7 @@ def test_determining_vat_rate
       product_id = SecureRandom.uuid
       another_product_id = SecureRandom.uuid
 
-      set_vat_rate(product_id, vat_rate)
+      set_vat_rate(product_id, vat_rate.code)
       vat_rate_determined = VatRateDetermined.new(data: { order_id: order_id, product_id: product_id, vat_rate: vat_rate })
       assert_events("Taxes::Order$#{order_id}", vat_rate_determined) do
         determine_vat_rate(order_id, product_id, vat_rate)
@@ -61,8 +61,8 @@ def test_should_not_allow_for_double_registration
 
     private
 
-    def set_vat_rate(product_id, vat_rate)
-      run_command(SetVatRate.new(product_id: product_id, vat_rate: vat_rate))
+    def set_vat_rate(product_id, vat_rate_code)
+      run_command(SetVatRate.new(product_id: product_id, vat_rate_code: vat_rate_code))
     end
 
     def determine_vat_rate(order_id, product_id, vat_rate)

ecommerce/taxes/test/vat_rate_catalog_test.rb

@@ -2,29 +2,21 @@
 
 module Taxes
   class VatRateCatalogTest < Test
-    class VatRateAvailableTest < VatRateCatalogTest
-      def test_returns_true_when_vat_rate_is_available
-        vat_rate = Infra::Types::VatRate.new(code: "50", rate: 50)
-        add_available_vat_rate(vat_rate)
-
-        assert catalog.vat_rate_available?(vat_rate.code)
+    class VatRateByCodeTest < VatRateCatalogTest
+      def setup
+        @vat_rate = Infra::Types::VatRate.new(code: "50", rate: 50)
+        add_available_vat_rate(@vat_rate)
       end
 
-      def test_returns_false_when_vat_rate_is_not_available
-        vat_rate = Infra::Types::VatRate.new(code: "50", rate: 50)
-
-        refute catalog.vat_rate_available?(vat_rate.code)
+      def test_returns_available_vat_rate
+        assert_equal @vat_rate, catalog.vat_rate_by_code("50")
       end
 
-      def test_returns_false_when_vat_rate_is_not_available_even_when_other_vat_rates_are_available
-        vat_rate = Infra::Types::VatRate.new(code: "50", rate: 50)
-        add_available_vat_rate(vat_rate)
-
-        refute catalog.vat_rate_available?("60")
+      def test_returns_nil_when_vat_rate_is_not_available
+        assert_nil catalog.vat_rate_by_code("60")
       end
     end
 
-
     private
 
     def catalog

rails_application/app/controllers/products_controller.rb

@@ -46,15 +46,15 @@ def create
       if product_form.vat_rate.present?
         set_product_vat_rate(product_form.product_id, product_form.vat_rate)
       end
-    rescue ProductCatalog::AlreadyRegistered
-      flash[:notice] = "Product was already registered"
-      render "new"
-    rescue Taxes::Product::VatRateNotApplicable
-      flash[:notice] = "Selected VAT rate not applicable"
-      render "new"
-    else
-      redirect_to products_path, notice: "Product was successfully created"
     end
+
+    redirect_to products_path, notice: "Product was successfully created"
+  rescue ProductCatalog::AlreadyRegistered
+    flash[:notice] = "Product was already registered"
+    render "new"
+  rescue Taxes::VatRateNotApplicable
+    flash[:notice] = "Selected VAT rate is not applicable"
+    render "new"
   end
 
   def update
@@ -92,7 +92,6 @@ def set_future_product_price(product_id, price, valid_since)
   end
 
   def set_product_vat_rate(product_id, vat_rate)
-    vat_rate = VatRates::AvailableVatRate.find_by!(code: vat_rate).to_value
     command_bus.(set_product_vat_rate_cmd(product_id, vat_rate))
   end
 
@@ -113,7 +112,7 @@ def set_product_price_cmd(product_id, price)
   end
 
   def set_product_vat_rate_cmd(product_id, vat_rate)
-    Taxes::SetVatRate.new(product_id: product_id, vat_rate: vat_rate)
+    Taxes::SetVatRate.new(product_id: product_id, vat_rate_code: vat_rate)
   end
 
   def set_product_future_price_cmd(product_id, price, valid_since)

rails_application/db/seeds.rb

@@ -59,7 +59,7 @@
     ProductCatalog::RegisterProduct.new(product_id: product_id),
     ProductCatalog::NameProduct.new(product_id: product_id, name: name_price_tuple[0]),
     Pricing::SetPrice.new(product_id: product_id, price: name_price_tuple[1]),
-    Taxes::SetVatRate.new(product_id: product_id, vat_rate: VatRates::AvailableVatRate.first.to_value)
+    Taxes::SetVatRate.new(product_id: product_id, vat_rate_code: "20")
   ].each do |command|
     command_bus.call(command)
   end

rails_application/test/integration/client_orders_test.rb

@@ -9,6 +9,7 @@ def setup
     ClientOrders::Client.destroy_all
     ClientOrders::Order.destroy_all
     Orders::Order.destroy_all
+    add_available_vat_rate(10)
   end
 
   def test_happy_path

rails_application/test/integration/customers_test.rb

@@ -1,6 +1,11 @@
 require "test_helper"
 
 class CustomersTest < InMemoryRESIntegrationTestCase
+  def setup
+    super
+    add_available_vat_rate(10)
+  end
+
   def test_list_customers
     get "/customers"
     assert_response :success

rails_application/test/integration/discount_test.rb

@@ -4,6 +4,7 @@ class DiscountTest < InMemoryRESIntegrationTestCase
   def setup
     super
     Orders::Order.destroy_all
+    add_available_vat_rate(10)
   end
 
   def test_reset_discount
@@ -40,4 +41,3 @@ def apply_discount_10_percent(order_id)
     assert_select("td", "$123.30")
   end
 end
-

rails_application/test/integration/orders_test.rb

@@ -5,6 +5,7 @@ def setup
     super
     Rails.configuration.payment_gateway.call.reset
     Orders::Order.destroy_all
+    add_available_vat_rate(10)
   end
 
   def test_submitting_empty_order

rails_application/test/integration/public_offer_test.rb

@@ -3,6 +3,7 @@
 class PublicOfferTest < InMemoryRESIntegrationTestCase
   def setup
     super
+    add_available_vat_rate(10)
   end
 
   def test_happy_path

rails_application/test/invoices/invoices_test.rb

@@ -29,27 +29,28 @@ def test_product_name_change_affects_existing_invoices
       product_id = SecureRandom.uuid
       initial_product_name = "Initial Name"
       updated_product_name = "Updated Name"
-
+
+      add_available_vat_rate(20)
       product_id = register_product(initial_product_name, 100, 20)
       customer_id = register_customer("Test Customer")
-      
+
       order_id = SecureRandom.uuid
       add_product_to_basket(order_id, product_id)
       submit_order(customer_id, order_id)
-      
+
       update_product_name(product_id, updated_product_name)
-      
+
       assert_invoice_product_name(order_id, initial_product_name)
 
       new_order_id = SecureRandom.uuid
       add_product_to_basket(new_order_id, product_id)
       submit_order(customer_id, new_order_id)
-  
+
       assert_invoice_product_name(new_order_id, updated_product_name)
     end
-    
+
     private
-    
+
     def update_product_name(product_id, new_name)
       patch "/products/#{product_id}",
             params: {
@@ -58,11 +59,11 @@ def update_product_name(product_id, new_name)
               name: new_name,
             }
     end
-    
+
     def assert_invoice_product_name(order_id, expected_name)
       get "/invoices/#{order_id}"
       assert_response :success
       assert_select ".py-2", text: expected_name
     end
   end
-end
+end

rails_application/test/test_helper.rb

@@ -81,7 +81,6 @@ def register_customer(name)
   end
 
   def register_product(name, price, vat_rate)
-    add_available_vat_rate(vat_rate)
     product_id = SecureRandom.uuid
     post "/products", params: { product_id: product_id, name: name, price: price, vat_rate: vat_rate }
     product_id