fixed foreign key determination (http://tammer.lighthouseapp.com/projects/5807/tickets/8)

git-svn-id: https://svn.thoughtbot.com/plugins/shoulda/trunk@287 7bbfaf0e-4d1d-0410-9690-a8bb5f8ef2aa

.autotest

@@ -1,8 +1,13 @@
 Autotest.add_hook :initialize do |at|
+  at.add_mapping(%r{^lib/\w.*\.rb}) do
+    at.files_matching(%r{^test/*/\w.*_test\.rb})
+  end
+
   at.add_mapping(%r{^test/rails_root/\w.*}) do
     at.files_matching(%r{^test/*/\w.*_test\.rb})
   end
 
   at.add_exception(%r{.svn})
   at.add_exception(%r{.log$})
+  at.add_exception(%r{^.autotest$})
 end

lib/shoulda/active_record_helpers.rb

@@ -302,7 +302,7 @@ module ThoughtBot # :nodoc:
               elsif reflection.options[:as]
                 fk = reflection.options[:as].to_s.foreign_key
               else
-                fk = klass.name.foreign_key
+                fk = reflection.primary_key_name
               end
               associated_klass = (reflection.options[:class_name] || association.to_s.classify).constantize
               assert associated_klass.column_names.include?(fk.to_s), "#{associated_klass.name} does not have a #{fk} foreign key."
@@ -367,7 +367,7 @@ module ThoughtBot # :nodoc:
 
             unless reflection.options[:polymorphic]
               associated_klass = (reflection.options[:class_name] || association.to_s.classify).constantize
-              fk = reflection.options[:foreign_key] || associated_klass.name.foreign_key
+              fk = reflection.options[:foreign_key] || reflection.primary_key_name
               assert klass.column_names.include?(fk.to_s), "#{klass.name} does not have a #{fk} foreign key."
             end
           end