Show items with same position in higher and lower items (#231)

* Show items with same position in higher and lower items
* Remove spacing, use update_column instead of update_columns

lib/acts_as_list/active_record/acts/list.rb

@@ -266,7 +266,8 @@ def higher_items(limit=nil)
           limit ||= acts_as_list_list.count
           position_value = send(position_column)
           acts_as_list_list.
-            where("#{quoted_position_column_with_table_name} < ?", position_value).
+            where("#{quoted_position_column_with_table_name} <= ?", position_value).
+            where("#{quoted_table_name}.#{self.class.primary_key} != ?", self.send(self.class.primary_key)).
             order("#{quoted_position_column_with_table_name} DESC").
             limit(limit)
         end
@@ -283,7 +284,8 @@ def lower_items(limit=nil)
           limit ||= acts_as_list_list.count
           position_value = send(position_column)
           acts_as_list_list.
-            where("#{quoted_position_column_with_table_name} > ?", position_value).
+            where("#{quoted_position_column_with_table_name} >= ?", position_value).
+            where("#{quoted_table_name}.#{self.class.primary_key} != ?", self.send(self.class.primary_key)).
             order("#{quoted_position_column_with_table_name} ASC").
             limit(limit)
         end

test/shared_list_sub.rb

@@ -85,6 +85,23 @@ def test_next_prev_groups
       assert_equal [], li1.higher_items
     end
 
+    def test_next_prev_groups_with_same_position
+      li1 = ListMixin.where(id: 1).first
+      li2 = ListMixin.where(id: 2).first
+      li3 = ListMixin.where(id: 3).first
+      li4 = ListMixin.where(id: 4).first
+
+      li3.update_column(:pos, 2) # Make the same position as li2
+
+      assert_equal [1, 2, 2, 4], ListMixin.pluck(:pos)
+
+      assert_equal [li3, li4], li2.lower_items
+      assert_equal [li2, li4], li3.lower_items
+
+      assert_equal [li3, li1], li2.higher_items
+      assert_equal [li2, li1], li3.higher_items
+    end
+
     def test_injection
       item = ListMixin.new("parent_id"=>1)
       assert_equal({ parent_id: 1 }, item.scope_condition)