Merge pull request solidusio#591 from brendandeere/pluggable_stock_es…

…timator

Allow the Stock::Estimator to be customized

core/app/models/spree/app_configuration.rb

@@ -17,6 +17,7 @@
 #
 require "spree/core/search/base"
 require "spree/core/search/variant"
+require 'spree/core/stock_configuration'
 
 module Spree
   class AppConfiguration < Preferences::Configuration
@@ -311,6 +312,10 @@ def static_model_preferences
       @static_model_preferences ||= Spree::Preferences::StaticModelPreferences.new
     end
 
+    def stock
+      Spree::StockConfiguration
+    end
+
     # all the following can be deprecated when store prefs are no longer supported
     # @private
     DEPRECATED_STORE_PREFERENCES = {

core/app/models/spree/shipment.rb

@@ -175,7 +175,7 @@ def refresh_rates
       # StockEstimator.new assigment below will replace the current shipping_method
       original_shipping_method_id = shipping_method.try!(:id)
 
-      new_rates = Stock::Estimator.new(order).shipping_rates(to_package)
+      new_rates = Spree::Config.stock.estimator_class.new(order).shipping_rates(to_package)
 
       # If one of the new rates matches the previously selected shipping
       # method, select that instead of the default provided by the estimator.

core/app/models/spree/stock/coordinator.rb

@@ -120,7 +120,7 @@ def prioritize_packages(packages)
       end
 
       def estimate_packages(packages)
-        estimator = Estimator.new(order)
+        estimator = Spree::Config.stock.estimator_class.new(order)
         packages.each do |package|
           package.shipping_rates = estimator.shipping_rates(package)
         end

core/lib/spree/core/stock_configuration.rb

@@ -0,0 +1,11 @@
+module Spree
+  module StockConfiguration
+    mattr_accessor :estimator_class do
+      '::Spree::Stock::Estimator'
+    end
+
+    def self.estimator_class
+      @@estimator_class.constantize
+    end
+  end
+end

core/spec/lib/spree/core/stock_configuration_spec.rb

@@ -0,0 +1,16 @@
+require 'spec_helper'
+
+RSpec.describe Spree::StockConfiguration do
+  before(:all) { @estimator_class = described_class.estimator_class.to_s }
+  after(:all)  { described_class.estimator_class = @estimator_class }
+
+  describe '.estimator_class' do
+    subject { described_class.estimator_class }
+    let(:foo) { Struct.new :foo }
+
+    before { described_class.estimator_class = 'Foo' }
+    before { Foo = foo }
+
+    it { is_expected.to eq foo }
+  end
+end

core/spec/models/spree/app_configuration_spec.rb

@@ -21,4 +21,8 @@
     expect(prefs.variant_search_class).to eq Spree::Core::Search::Variant
   end
 
+  describe '#stock' do
+    subject { prefs.stock }
+    it { is_expected.to eq Spree::StockConfiguration }
+  end
 end

core/spec/models/spree/shipment_spec.rb

@@ -207,6 +207,11 @@
         expect(shipment.refresh_rates).to eq([])
       end
 
+      it 'uses the pluggable estimator class' do
+        expect(Spree::StockConfiguration).to receive(:estimator_class).and_call_original
+        shipment.refresh_rates
+      end
+
       context 'to_package' do
         let(:inventory_units) do
           [build(:inventory_unit, line_item: line_item, variant: variant, state: 'on_hand'),

core/spec/models/spree/stock/coordinator_spec.rb

@@ -15,6 +15,11 @@ module Stock
           expect(subject).to receive(:estimate_packages).ordered
           subject.packages
         end
+
+        it 'uses the pluggable estimator class' do
+          expect(Spree::StockConfiguration).to receive(:estimator_class).and_call_original
+          subject.packages
+        end
       end
 
       describe "#shipments" do