Adding a standard variant upon initialisation of a new instance of Spree::Product

app/models/spree/product_decorator.rb

@@ -32,6 +32,7 @@ Spree::Product.class_eval do
   validates_presence_of :variant_unit_name,
                         if: -> p { p.variant_unit == 'items' }
 
+  after_initialize :ensure_first_standard_variant, :if => :new_record?
   after_initialize :set_available_on_to_now, :if => :new_record?
   after_save :update_units
   after_touch :touch_distributors
@@ -205,4 +206,7 @@ Spree::Product.class_eval do
     Spree::OptionType.where('name LIKE ?', 'unit_%%')
   end
 
+  def ensure_first_standard_variant
+    self.variants << Spree::Variant.new
+  end
 end

spec/models/spree/product_spec.rb

@@ -85,6 +85,14 @@ module Spree
           end
         end
 
+        context "instatiating a new product" do
+          let!(:product) { Spree::Product.new }
+
+          it "creates a standard (non-master) variant when created" do
+            product.variants.should_not be_empty
+          end
+        end
+
         context "when the unit is items" do
           it "is valid when unit name is set and unit scale is not" do
             product.variant_unit = 'items'
@@ -122,7 +130,6 @@ module Spree
         end
       end
     end
-    
 
     describe "scopes" do
       describe "in_supplier" do