Add an event that is fired when any shipment ships

Transactions need to be reported to TaxJar when any of the shipment
ships (some stores have partial shipping). To accomodate this, we
add a new event which is fired whenever any shipment on an order ships.

Co-authored-by: Nick Van Doorn <nick@super.gd>

2 files changed, 34 insertions, 0 deletions

diff --git a/app/decorators/super_good/solidus_taxjar/spree/shipment/fire_shipment_shipped_event.rb b/app/decorators/super_good/solidus_taxjar/spree/shipment/fire_shipment_shipped_event.rb
new file mode 100644
index 0000000..a109745
--- /dev/null
+++ b/app/decorators/super_good/solidus_taxjar/spree/shipment/fire_shipment_shipped_event.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+module SuperGood
+  module SolidusTaxjar
+    module Spree
+      module Shipment
+        module FireShipmentShippedEvent
+          def after_ship
+            ::Spree::Event.fire 'shipment_shipped', shipment: self
+            super
+          end
+
+          ::Spree::Shipment.prepend(self)
+        end
+      end
+    end
+  end
+end
diff --git a/spec/models/spree/shipment_spec.rb b/spec/models/spree/shipment_spec.rb
new file mode 100644
index 0000000..27f213b
--- /dev/null
+++ b/spec/models/spree/shipment_spec.rb
@@ -0,0 +1,16 @@
+RSpec.describe Spree::Shipment do
+  describe '#update' do
+    subject { shipment.ship }
+
+    let(:shipment) { create(:shipment, state: 'ready', order: order) }
+    let(:order) { create :order_with_line_items }
+
+    it 'fires the shipment_shipped event exactly once' do
+      stub_const('Spree::Event', class_spy(Spree::Event))
+
+      expect(Spree::Event).to receive(:fire).with('shipment_shipped', shipment: shipment).once
+
+      subject
+    end
+  end
+end