after saving the model, we set the primary key within the fixture has…

…h, in case it was not explicitly specified in the fixture and was generated by an auto_increment / serial field

lib/fixture_dependencies.rb

@@ -149,8 +149,13 @@ def use(record, loading = [], procs = {})
       puts "#{spaces}#{record}.#{attr} = #{value.inspect}" if verbose > 2
       obj.send("#{attr}=", value)
     end
+
     puts "#{spaces}saving #{record}" if verbose > 1
+
     model_method(:model_save, mtype, obj)
+    # after saving the model, we set the primary key within the fixture hash, in case it was not explicitly specified in the fixture and was generated by an auto_increment / serial field
+    fixtures[model_name.to_sym][name.to_sym][model.primary_key.to_sym] ||= obj[model.primary_key.to_sym]
+
     loading.pop
     # Update the circular references 
     if procs[record]