do not store GroupOrderArticles with zero quantity and tolerance

app/models/group_order_article.rb

@@ -13,7 +13,7 @@ class GroupOrderArticle < ActiveRecord::Base
   validates_inclusion_of :tolerance, :in => 0..99
   validates_uniqueness_of :order_article_id, :scope => :group_order_id    # just once an article per group order
 
-  scope :ordered, -> { includes(:group_order => :ordergroup).where('group_order_articles.result > 0 OR group_order_articles.quantity > 0 OR group_order_articles.tolerance > 0').order('groups.name') }
+  scope :ordered, -> { includes(:group_order => :ordergroup).order(:groups => :name) }
 
   localize_input_of :result
 
@@ -35,6 +35,13 @@ class GroupOrderArticle < ActiveRecord::Base
     logger.debug("GroupOrderArticle[#{id}].update_quantities(#{quantity}, #{tolerance})")
     logger.debug("Current quantity = #{self.quantity}, tolerance = #{self.tolerance}")
 
+    # When quantity and tolerance are zero, we don't serve any purpose
+    if quantity == 0 and tolerance == 0
+      logger.debug("Self-destructing since requested quantity and tolerance are zero")
+      destroy!
+      return
+    end
+
     # Get quantities ordered with the newest item first.
     quantities = group_order_article_quantities.order('created_on DESC').to_a
     logger.debug("GroupOrderArticleQuantity items found: #{quantities.size}")

db/migrate/20140318173000_delete_empty_group_order_articles.rb

@@ -0,0 +1,9 @@
+class DeleteEmptyGroupOrderArticles < ActiveRecord::Migration
+  def up
+    # up until recently, group_order_articles with all quantities zero were saved
+    GroupOrderArticle.where(quantity: 0, tolerance: 0, result: [0, nil], result_computed: [0, nil]).delete_all
+  end
+
+  def down
+  end
+end

spec/integration/receive_spec.rb

@@ -22,15 +22,16 @@ describe 'receiving an order', :type => :feature do
 
   # reload all group_order_articles
   def reload_articles
-    [goa1, goa2].map(&:reload)
+    goa1.reload unless goa1.destroyed?
+    goa2.reload unless goa2.destroyed?
     oa.reload
   end
 
   def check_quantities(units, q1, q2)
     reload_articles
     expect(oa.units).to eq units
-    expect(goa1.result).to be_within(1e-3).of q1
-    expect(goa2.result).to be_within(1e-3).of q2
+    expect(goa1.destroyed? ? 0 : goa1.result).to be_within(1e-3).of q1
+    expect(goa2.destroyed? ? 0 : goa2.result).to be_within(1e-3).of q2
   end
 
 

spec/models/group_order_article_spec.rb

@@ -9,7 +9,6 @@ describe GroupOrderArticle do
   it 'has zero quantity by default'    do expect(goa.quantity).to eq(0) end
   it 'has zero tolerance by default'   do expect(goa.tolerance).to eq(0) end
   it 'has zero result by default'      do expect(goa.result).to eq(0) end
-  it 'is not ordered by default'       do expect(GroupOrderArticle.ordered.where(:id => goa.id).exists?).to be_false end
   it 'has zero total price by default' do expect(goa.total_price).to eq(0) end
 
   describe do
@@ -39,8 +38,7 @@ describe GroupOrderArticle do
     it 'can unorder a product' do
       goa.update_quantities(rand(1..99), rand(0..99))
       goa.update_quantities(0, 0)
-      expect(goa.quantity).to eq(0)
-      expect(goa.tolerance).to eq(0)
+      expect(GroupOrderArticle.exists?(goa.id)).to be_false
     end
   end