Deprecate including Benefit modules

In the unlikely case people have used these modules, warn if they are
included.

Author: mamhoff

promotions/app/models/concerns/solidus_promotions/benefits/line_item_benefit.rb

@@ -3,6 +3,10 @@
 module SolidusPromotions
   module Benefits
     module LineItemBenefit
+      def self.included(_base)
+        Spree.deprecator.warn("Including #{name} is deprecated.")
+      end
+
       def can_discount?(object)
         object.is_a? Spree::LineItem
       end

promotions/app/models/concerns/solidus_promotions/benefits/order_benefit.rb

@@ -3,6 +3,10 @@
 module SolidusPromotions
   module Benefits
     module OrderBenefit
+      def self.included(_base)
+        Spree.deprecator.warn("Including #{name} is deprecated.")
+      end
+
       def can_discount?(_)
         false
       end

promotions/app/models/concerns/solidus_promotions/benefits/shipment_benefit.rb

@@ -3,6 +3,10 @@
 module SolidusPromotions
   module Benefits
     module ShipmentBenefit
+      def self.included(_base)
+        Spree.deprecator.warn("Including #{name} is deprecated.")
+      end
+
       def can_discount?(object)
         object.is_a?(Spree::Shipment) || object.is_a?(Spree::ShippingRate)
       end

promotions/spec/models/solidus_promotions/benefits/line_item_benefit_spec.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+RSpec.describe SolidusPromotions::Benefits::LineItemBenefit do
+  subject(:benefit_class) do
+    Class.new(SolidusPromotions::Benefit) do
+      include SolidusPromotions::Benefits::LineItemBenefit
+    end
+  end
+
+  it "warns" do
+    expect(Spree.deprecator).to receive(:warn).with(
+      "Including SolidusPromotions::Benefits::LineItemBenefit is deprecated."
+    )
+    subject
+  end
+end

promotions/spec/models/solidus_promotions/benefits/order_benefit_spec.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+RSpec.describe SolidusPromotions::Benefits::OrderBenefit do
+  subject(:benefit_class) do
+    Class.new(SolidusPromotions::Benefit) do
+      include SolidusPromotions::Benefits::OrderBenefit
+    end
+  end
+
+  it "warns" do
+    expect(Spree.deprecator).to receive(:warn).with(
+      "Including SolidusPromotions::Benefits::OrderBenefit is deprecated."
+    )
+    subject
+  end
+end

promotions/spec/models/solidus_promotions/benefits/shipment_benefit_spec.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+RSpec.describe SolidusPromotions::Benefits::ShipmentBenefit do
+  subject(:benefit_class) do
+    Class.new(SolidusPromotions::Benefit) do
+      include SolidusPromotions::Benefits::ShipmentBenefit
+    end
+  end
+
+  it "warns" do
+    expect(Spree.deprecator).to receive(:warn).with(
+      "Including SolidusPromotions::Benefits::ShipmentBenefit is deprecated."
+    )
+    subject
+  end
+end