category is not "positionable"

spec/components/concern/positionable_spec.rb

@@ -0,0 +1,52 @@
+require "spec_helper"
+require_dependency "concern/positionable"
+
+describe Concern::Positionable do
+
+  def positions
+    TestItem.order('position asc, id asc').pluck(:id)
+  end
+
+  context "move_to" do
+    before do
+      class TestItem < ActiveRecord::Base
+        include Concern::Positionable
+      end
+
+      Topic.exec_sql("create temporary table test_items(id int primary key, position int)")
+    end
+
+    after do
+      Topic.exec_sql("drop table test_items")
+
+      # import is making my life hard, we need to nuke this out of orbit
+      des = ActiveSupport::DescendantsTracker.class_variable_get :@@direct_descendants
+      des[ActiveRecord::Base].delete(TestItem)
+      Object.send(:remove_const, :TestItem)
+    end
+
+    it "can position stuff correctly" do
+      5.times do |i|
+        Topic.exec_sql("insert into test_items(id,position) values(#{i}, #{i})")
+      end
+
+      positions.should == [0,1,2,3,4]
+      TestItem.find(3).move_to(0)
+      positions.should == [3,0,1,2,4]
+      TestItem.pluck(:position).sort.should == [0,1,2,3,4]
+
+
+      # this is somewhat odd, but when there is not positioning
+      # not much we can do
+      TestItem.find(1).move_to(5)
+      positions.should == [3,0,2,4,1]
+
+      TestItem.pluck(:position).sort.should == [0,1,2,3,4]
+
+      item = TestItem.new
+      item.id = 7
+      item.save
+      item.position.should == 5
+    end
+  end
+end