get rid of technical events in ReservationProcess

Instead, just use exception to pass unavailable products list

Author: porbas

ecommerce/pricing/lib/pricing/commands.rb

@@ -111,6 +111,8 @@ class AcceptOffer < Infra::Command
 
   class RejectOffer < Infra::Command
     attribute :order_id, Infra::Types::UUID
+    attribute :reason, Infra::Types::String
+    attribute? :unavailable_products, Infra::Types::Array.of(Infra::Types::UUID)
 
     alias aggregate_id order_id
   end

ecommerce/pricing/lib/pricing/events.rb

@@ -86,6 +86,8 @@ class OfferAccepted < Infra::Event
 
   class OfferRejected < Infra::Event
     attribute :order_id, Infra::Types::UUID
+    attribute :reason, Infra::Types::String
+    attribute? :unavailable_product_ids, Infra::Types::Array.of(Infra::Types::UUID)
   end
 
   class OfferExpired < Infra::Event

ecommerce/pricing/lib/pricing/offer.rb

@@ -137,9 +137,13 @@ def accept
       )
     end
 
-    def reject
+    def reject(reason, unavailable_product_ids)
       raise InvalidState.new("Only accepted offer can be rejected") unless @state == :accepted
-      apply OfferRejected.new(data: { order_id: @id })
+      apply OfferRejected.new(data: {
+        order_id: @id,
+        reason:,
+        unavailable_product_ids:
+      })
     end
 
     def expire

ecommerce/pricing/lib/pricing/services.rb

@@ -228,7 +228,7 @@ def initialize(event_store)
 
     def call(command)
       @repository.with_aggregate(Offer, command.aggregate_id) do |order|
-        order.reject
+        order.reject(command.reason, command.unavailable_products)
       end
     end
   end

ecommerce/processes/.mutant.yml

@@ -18,6 +18,6 @@ matcher:
     - Processes::SyncInventoryFromOrdering*
     - Processes::NotifyPaymentsAboutOrderValue*
     - Processes::ThreePlusOneFree*
-    - Processes::ReservationProcess#build_state
+    - Processes::ReservationProcess*
     - Processes::ReservationProcess::ProcessState#call
     - Processes::DetermineVatRatesOnOrderPlaced*

ecommerce/processes/lib/processes.rb

@@ -9,7 +9,6 @@
 require_relative "../../invoicing/lib/invoicing"
 require_relative "../../fulfillment/lib/fulfillment"
 require_relative 'processes/confirm_order_on_payment_captured'
-require_relative 'processes/events'
 require_relative 'processes/release_payment_process'
 require_relative 'processes/shipment_process'
 require_relative 'processes/determine_vat_rates_on_order_placed'

ecommerce/processes/lib/processes/events.rb

@@ -2,6 +2,14 @@ module Processes
   class ReservationProcess
     include Infra::Retry
 
+    class SomeInventoryNotAvailable < StandardError
+      attr_reader :unavailable_products
+
+      def initialize(unavailable_products)
+        @unavailable_products = unavailable_products
+      end
+    end
+
     def initialize(event_store, command_bus)
       @event_store = event_store
       @command_bus = command_bus
@@ -31,21 +39,17 @@ def reserve_stock(state)
         unavailable_products << product_id
       end
 
-      if unavailable_products.empty?
-        event = ReservationProcessSuceeded.new(data: { order_id: state.order_id })
-      else
+      unless unavailable_products.empty?
         release_stock(state)
-        event = ReservationProcessFailed.new(data: { order_id: state.order_id, unavailable_products: unavailable_products })
+        raise SomeInventoryNotAvailable.new(unavailable_products)
       end
-      event_store.publish(event, stream_name: stream_name(state.order_id))
     end
 
     def update_order_state(state)
-      event_store
-      .within { yield }
-      .subscribe(to: ReservationProcessFailed) { reject_order(state) }
-      .subscribe(to: ReservationProcessSuceeded) { accept_order(state) }
-      .call
+      yield
+      accept_order(state)
+    rescue SomeInventoryNotAvailable => exc
+      reject_order(state, exc.unavailable_products)
     end
 
     def release_stock(state)
@@ -64,8 +68,10 @@ def accept_order(state)
       command_bus.(Fulfillment::RegisterOrder.new(order_id: state.order_id))
     end
 
-    def reject_order(state)
-      command_bus.(Pricing::RejectOffer.new(order_id: state.order_id))
+    def reject_order(state, unavailable_products)
+      command_bus.(Pricing::RejectOffer.new(
+        order_id: state.order_id, reason: "Some products were unavailable", unavailable_products: )
+      )
     end
 
     def stream_name(order_id)

ecommerce/processes/lib/processes/reservation_process.rb

@@ -6,9 +6,9 @@ class ReservationProcessTest < Test
 
     def test_happy_path
       process = ReservationProcess.new(event_store, command_bus)
-      assert_success_event do
-        given([offer_accepted]).each { |event| process.call(event) }
-      end
+
+      given([offer_accepted]).each { |event| process.call(event) }
+
       assert_all_commands(
         Inventory::Reserve.new(product_id: product_id, quantity: 1),
         Inventory::Reserve.new(product_id: another_product_id, quantity: 2),
@@ -33,14 +33,13 @@ def test_rejects_order_and_compensates_stock_when_sth_is_unavailable
       enhanced_command_bus = EnhancedFakeCommandBus.new(command_bus, failing_command => Inventory::InventoryEntry::InventoryNotAvailable)
       process = ReservationProcess.new(event_store, enhanced_command_bus)
 
-      assert_failure_event do
-        given([offer_accepted]).each { |event| process.call(event) }
-      end
+      given([offer_accepted]).each { |event| process.call(event) }
+
       assert_all_commands(
         failing_command,
         Inventory::Reserve.new(product_id: another_product_id, quantity: 2),
         Inventory::Release.new(product_id: another_product_id, quantity: 2),
-        Pricing::RejectOffer.new(order_id: order_id),
+        Pricing::RejectOffer.new(order_id: order_id, reason: "Some products were unavailable", unavailable_products: [product_id]),
       )
     end
 
@@ -97,21 +96,5 @@ def order_cancelled
         }
       )
     end
-
-    def assert_success_event(&block)
-      assert_events_contain(
-        "ReservationProcess$#{order_id}",
-        ReservationProcessSuceeded.new(data: { order_id: order_id }),
-        &block
-      )
-    end
-
-    def assert_failure_event(&block)
-      assert_events_contain(
-        "ReservationProcess$#{order_id}",
-        ReservationProcessFailed.new(data: { order_id: order_id, unavailable_products: [product_id] }),
-        &block
-      )
-    end
   end
 end