Factory evaluators use inheritance

lib/factory_girl/attribute_assigner.rb

@@ -2,10 +2,10 @@
 
 module FactoryGirl
   class AttributeAssigner
-    def initialize(build_class, evaluator, attribute_list)
+    def initialize(build_class, evaluator)
       @build_class              = build_class
       @evaluator                = evaluator
-      @attribute_list           = attribute_list
+      @attribute_list           = evaluator.class.attribute_list
       @attribute_names_assigned = []
     end
 

lib/factory_girl/evaluator.rb

@@ -1,13 +1,24 @@
+require "active_support/core_ext/class/attribute"
+
 module FactoryGirl
   class Evaluator
+    class_attribute :callbacks, :attribute_lists
+
+    def self.attribute_list
+      AttributeList.new.tap do |list|
+        attribute_lists.each do |attribute_list|
+          list.apply_attributes attribute_list.to_a
+        end
+      end
+    end
     undef_method(:id) if method_defined?(:id)
 
-    def initialize(build_strategy, overrides = {}, callbacks = [])
+    def initialize(build_strategy, overrides = {})
       @build_strategy    = build_strategy
       @overrides         = overrides
       @cached_attributes = overrides
 
-      @build_strategy.add_observer(CallbackRunner.new(callbacks, self))
+      @build_strategy.add_observer(CallbackRunner.new(self.class.callbacks, self))
     end
 
     delegate :association, :to => :@build_strategy

lib/factory_girl/evaluator_class_definer.rb

@@ -1,13 +1,22 @@
 module FactoryGirl
   class EvaluatorClassDefiner
-    def initialize(attributes)
+    def initialize(attributes, callbacks, parent_class)
+      @parent_class = parent_class
+      @callbacks    = callbacks
+      @attributes   = attributes
+
       attributes.each do |attribute|
         define_attribute(attribute.name, attribute.to_proc)
       end
     end
 
     def evaluator_class
-      @evaluator_class ||= Class.new(FactoryGirl::Evaluator)
+      @evaluator_class ||= Class.new(@parent_class).tap do |klass|
+        klass.callbacks ||= []
+        klass.callbacks += @callbacks
+        klass.attribute_lists ||= []
+        klass.attribute_lists += [@attributes]
+      end
     end
 
     private

lib/factory_girl/factory.rb

@@ -40,8 +40,8 @@ def run(proxy_class, overrides, &block) #:nodoc:
 
       proxy = proxy_class.new
 
-      evaluator = evaluator_class_definer.evaluator_class.new(proxy, overrides.symbolize_keys, callbacks)
-      attribute_assigner = AttributeAssigner.new(build_class, evaluator, attributes)
+      evaluator = evaluator_class.new(proxy, overrides.symbolize_keys)
+      attribute_assigner = AttributeAssigner.new(build_class, evaluator)
 
       proxy.result(attribute_assigner, to_create).tap(&block)
     end
@@ -104,6 +104,10 @@ def class_name #:nodoc:
       @class_name || parent.class_name || name
     end
 
+    def evaluator_class
+      @evaluator_class ||= EvaluatorClassDefiner.new(attributes, callbacks, parent.evaluator_class).evaluator_class
+    end
+
     def attributes
       compile
       AttributeList.new(@name).tap do |list|
@@ -120,7 +124,7 @@ def callbacks
     private
 
     def processing_order
-      [parent, traits.reverse, @definition].flatten
+      [traits.reverse, @definition].flatten
     end
 
     def assert_valid_options(options)
@@ -145,9 +149,5 @@ def initialize_copy(source)
       super
       @definition = @definition.clone
     end
-
-    def evaluator_class_definer
-      @evaluator_class_definer ||= EvaluatorClassDefiner.new(attributes)
-    end
   end
 end

lib/factory_girl/null_factory.rb

@@ -11,5 +11,6 @@ def initialize
     def compile; end
     def class_name; end
     def default_strategy; :create; end
+    def evaluator_class; FactoryGirl::Evaluator; end
   end
 end

spec/factory_girl/evaluator_class_definer_spec.rb

@@ -4,9 +4,10 @@
   let(:simple_attribute)                    { stub("simple attribute",   :name => :simple, :to_proc => lambda { 1 }) }
   let(:relative_attribute)                  { stub("relative attribute", :name => :relative, :to_proc => lambda { simple + 1 }) }
   let(:attribute_that_raises_a_second_time) { stub("attribute that would raise without a cache", :name => :raises_without_proper_cache, :to_proc => lambda { raise "failed" if @run; @run = true; nil }) }
+  let(:callbacks) { [stub("callback 1"), stub("callback 2")] }
 
   let(:attributes)    { [simple_attribute, relative_attribute, attribute_that_raises_a_second_time] }
-  let(:class_definer) { FactoryGirl::EvaluatorClassDefiner.new(attributes) }
+  let(:class_definer) { FactoryGirl::EvaluatorClassDefiner.new(attributes, callbacks, FactoryGirl::Evaluator) }
   let(:evaluator)     { class_definer.evaluator_class.new(stub("build strategy", :add_observer => true)) }
 
   it "returns an evaluator when accessing the evaluator class" do
@@ -26,4 +27,28 @@
       2.times { evaluator.raises_without_proper_cache }
     }.to_not raise_error
   end
+
+  it "sets attributes on the evaluator class" do
+    class_definer.evaluator_class.attribute_lists.should == [attributes]
+  end
+
+  it "sets callbacks on the evaluator class" do
+    class_definer.evaluator_class.callbacks.should == callbacks
+  end
+
+  context "with a custom evaluator as a parent class" do
+    let(:child_callbacks)  { [stub("child callback 1"), stub("child callback 2")] }
+    let(:child_attributes) { [stub("child attribute", :name => :simple, :to_proc => lambda { 1 })] }
+    let(:child_definer)    { FactoryGirl::EvaluatorClassDefiner.new(child_attributes, child_callbacks, class_definer.evaluator_class) }
+
+    subject { child_definer.evaluator_class }
+
+    it "bases its attribute lists on itself and its parent evaluator" do
+      subject.attribute_lists.should == [attributes, child_attributes]
+    end
+
+    it "bases its callbacks on itself and its parent evaluator" do
+      subject.callbacks.should == callbacks + child_callbacks
+    end
+  end
 end

spec/factory_girl/null_factory_spec.rb

@@ -9,4 +9,5 @@
   its(:class_name)       { should be_nil }
   its(:default_strategy) { should == :create }
   its(:attributes)       { should be_an_instance_of(FactoryGirl::AttributeList) }
+  its(:evaluator_class)  { should == FactoryGirl::Evaluator }
 end