Add OrderCycle distributing_product scope

app/models/order_cycle.rb

@@ -12,6 +12,10 @@ class OrderCycle < ActiveRecord::Base
   scope :active, lambda { where('orders_open_at <= ? AND orders_close_at >= ?', Time.now, Time.now) }
   scope :inactive, lambda { where('orders_open_at > ? OR orders_close_at < ?', Time.now, Time.now) }
 
+  scope :distributing_product, lambda { |product| joins(:exchanges => :variants).
+    where('exchanges.sender_id = order_cycles.coordinator_id').
+    where('spree_variants.id IN (?)', product.variants_including_master.map(&:id)).
+    select('DISTINCT order_cycles.*') }
 
   def suppliers
     self.exchanges.where(:receiver_id => self.coordinator).map(&:sender).uniq

spec/models/order_cycle_spec.rb

@@ -40,6 +40,33 @@ describe OrderCycle do
     OrderCycle.inactive.sort.should == [oc_not_yet_open, oc_already_closed].sort
   end
 
+  describe "finding order cycles distributing a product" do
+    it "returns order cycles distributing the product's master variant" do
+      p = create(:product)
+      d = create(:distributor_enterprise)
+      oc = create(:simple_order_cycle, distributors: [d], variants: [p.master])
+      OrderCycle.distributing_product(p).should == [oc]
+    end
+
+    it "returns order cycles distributing another variant" do
+      p = create(:product)
+      v = create(:variant, product: p)
+      d = create(:distributor_enterprise)
+      oc = create(:simple_order_cycle, distributors: [d], variants: [v])
+      OrderCycle.distributing_product(p).should == [oc]
+    end
+
+    it "does not return order cycles supplying but not distributing a product" do
+      p = create(:product)
+      s = create(:supplier_enterprise)
+      oc = create(:simple_order_cycle)
+      ex = create(:exchange, order_cycle: oc, sender: s, receiver: oc.coordinator)
+      ex.variants << p.master
+
+      OrderCycle.distributing_product(p).should == []
+    end
+  end
+
   it "reports its suppliers" do
     oc = create(:simple_order_cycle)