Add specs for #1532.

core/spec/lib/generators/refinery/engine/engine_generator_spec.rb

@@ -80,5 +80,20 @@ module Refinery
         end
       }
     end
+
+    context "when generating extension inside existing extensions dir" do
+      before do
+        Refinery::EngineGenerator.any_instance.stub(:merge_locales!).and_return(true)
+        Refinery::EngineGenerator.any_instance.stub(:existing_extension?).and_return(true)
+
+        run_generator %w{ rspec_item_test title:string --extension rspec_product_tests --skip }
+      end
+
+      it "appends existing seeds file" do
+        File.open("#{destination_root}/vendor/extensions/rspec_product_tests/db/seeds.rb") do |file|
+          file.grep(%r{/rspec_product_tests|/rspec_item_tests}).count.should eq(2)
+        end
+      end
+    end
   end
 end