Add Discountable module to shipping rates

Author: mamhoff

promotions/app/patches/models/solidus_promotions/shipping_rate_patch.rb

@@ -23,6 +23,13 @@ def promo_total
       discounts.sum(&:amount)
     end
 
+    def discounts_by_lanes(lanes)
+      discounts.select do |discount|
+        discount.benefit.promotion.lane.to_sym.in?(lanes.map(&:to_sym))
+      end
+    end
+
+    Spree::ShippingRate.prepend SolidusPromotions::Discountable
     Spree::ShippingRate.prepend SolidusPromotions::DiscountableAmount
     Spree::ShippingRate.prepend self
   end

promotions/spec/models/spree/shipping_rate_spec.rb

@@ -75,4 +75,86 @@
       expect { subject }.to change { shipping_rate.current_discounts.length }.from(1).to(0)
     end
   end
+
+  describe "#previous_lane_discounts" do
+    let(:order) { Spree::Order.new }
+    let(:shipment) { Spree::Shipment.new(order:) }
+    let(:tax_rate) { create(:tax_rate) }
+    let(:pre_lane_promotion) { create(:solidus_promotion, :with_adjustable_benefit, lane: :pre) }
+    let(:post_lane_promotion) { create(:solidus_promotion, :with_adjustable_benefit, lane: :post) }
+    let(:shipping_rate) { Spree::ShippingRate.new(discounts:, shipment:) }
+    let(:discounts) { [pre_lane_discount, post_lane_discount] }
+    let(:pre_lane_discount) { SolidusPromotions::ShippingRateDiscount.new(benefit: pre_lane_promotion.benefits.first) }
+    let(:post_lane_discount) { SolidusPromotions::ShippingRateDiscount.new(benefit: post_lane_promotion.benefits.first) }
+
+    subject { shipping_rate.previous_lane_discounts }
+
+    it "raises unless we're doing a promotion calculation" do
+      expect { subject }.to raise_exception(SolidusPromotions::NotCalculatingPromotions)
+    end
+
+    context "while calculating promotions" do
+      around do |example|
+        SolidusPromotions::Promotion.within_lane(lane) do
+          example.run
+        end
+      end
+
+      let(:lane) { "pre" }
+      it { is_expected.to be_empty }
+
+      context "if lane is default" do
+        let(:lane) { "default" }
+
+        it { is_expected.to contain_exactly(pre_lane_discount) }
+      end
+
+      context "if lane is post" do
+        let(:lane) { "post" }
+
+        it { is_expected.to contain_exactly(pre_lane_discount) }
+      end
+    end
+  end
+
+  describe "#current_lane_discounts" do
+    let(:order) { Spree::Order.new }
+    let(:shipment) { Spree::Shipment.new(order:) }
+    let(:tax_rate) { create(:tax_rate) }
+    let(:pre_lane_promotion) { create(:solidus_promotion, :with_adjustable_benefit, lane: :pre) }
+    let(:post_lane_promotion) { create(:solidus_promotion, :with_adjustable_benefit, lane: :post) }
+    let(:shipping_rate) { Spree::ShippingRate.new(discounts:, shipment:) }
+    let(:discounts) { [pre_lane_discount, post_lane_discount] }
+    let(:pre_lane_discount) { SolidusPromotions::ShippingRateDiscount.new(benefit: pre_lane_promotion.benefits.first) }
+    let(:post_lane_discount) { SolidusPromotions::ShippingRateDiscount.new(benefit: post_lane_promotion.benefits.first) }
+
+    subject { shipping_rate.current_lane_discounts }
+
+    it "raises unless we're doing a promotion calculation" do
+      expect { subject }.to raise_exception(SolidusPromotions::NotCalculatingPromotions)
+    end
+
+    context "while calculating promotions" do
+      around do |example|
+        SolidusPromotions::Promotion.within_lane(lane) do
+          example.run
+        end
+      end
+
+      let(:lane) { "pre" }
+      it { is_expected.to contain_exactly(pre_lane_discount) }
+
+      context "if lane is default" do
+        let(:lane) { "default" }
+
+        it { is_expected.to be_empty }
+      end
+
+      context "if lane is post" do
+        let(:lane) { "post" }
+
+        it { is_expected.to contain_exactly(post_lane_discount) }
+      end
+    end
+  end
 end