Added primary_key support for has_one same as has_many

lib/associations/associations.rb

@@ -116,15 +116,16 @@ def has_one(association_id, options = {})
         define_method(association_id) do
           options = {
             :class_name => association_id.to_s.classify,
-            :foreign_key => self.class.to_s.foreign_key
+            :foreign_key => self.class.to_s.foreign_key,
+            :primary_key => self.class.primary_key
           }.merge(options)
 
           scope = options[:class_name].constantize
 
           if scope.respond_to?(:scoped) && options[:conditions]
             scope = scope.scoped(:conditions => options[:conditions])
           end
-          scope.send("find_by_#{options[:foreign_key]}", id)
+          scope.send("find_by_#{options[:foreign_key]}", send(options[:primary_key]))
         end
       end
 

spec/associations/associations_spec.rb

@@ -156,20 +156,67 @@ class SchoolStatus < ActiveHash::Base
 
   describe "#has_one" do
     context "with ActiveHash children" do
-      before do
-        City.has_one :author
-        Author.field :city_id
+      context "with default options" do
+        before do
+          Author.field :city_id
+          City.has_one :author
+        end
+
+        it "find the correct records" do
+          author = Author.create :city_id => 1
+          city = City.create :id => 1
+          expect(city.author).to eq(author)
+        end
+
+        it "returns nil when there are no records" do
+          Author.create :city_id => 10
+          city = City.create :id => 1
+          expect(city.author).to be_nil
+        end
       end
 
-      it "find the correct records" do
-        city = City.create :id => 1
-        author = Author.create :city_id => 1
-        expect(city.author).to eq(author)
+      context "with a primary_key option" do
+        before do
+          Author.field :city_id
+          City.field :author_identifier
+          City.has_one :author, :primary_key => :author_identifier
+        end
+
+        it "find the correct records" do
+          Author.create :city_id => 1
+          author = Author.create :city_id => 10
+          city = City.create :id => 1, :author_identifier => 10
+          expect(city.author).to eq(author)
+        end
+
+        it "returns nil when there are no records" do
+          Author.create :city_id => 1
+          city = City.create :id => 1, :author_identifier => 10
+          expect(city.author).to be_nil
+        end
       end
 
-      it "returns nil when there are no records" do
-        city = City.create :id => 1
-        expect(city.author).to be_nil
+      context "with a foreign_key option" do
+        before do
+          Author.field :city_id
+          Author.field :city_identifier
+          City.has_one :author, :foreign_key => :city_identifier
+        end
+
+        it "find the correct records" do
+          Author.create :city_id => 1, :city_identifier => 1
+          author = Author.create :city_id => 1, :city_identifier => 10
+          Author.create :city_id => 10, :city_identifier => 5
+          city = City.create :id => 10
+          expect(city.author).to eq(author)
+        end
+
+        it "returns nil when there are no records" do
+          Author.create :city_id => 1, :city_identifier => 1
+          Author.create :city_id => 10, :city_identifier => 5
+          city = City.create :id => 10
+          expect(city.author).to be_nil
+        end
       end
     end
   end