Add separate test for :ignore attribute.

test/dummy/app/models/legacy_widget.rb

@@ -1,3 +1,4 @@
 class LegacyWidget < ActiveRecord::Base
-  has_paper_trail :version_name => 'custom_version'
+  has_paper_trail :ignore => :version,
+                  :version_name => 'custom_version'
 end

test/unit/model_test.rb

@@ -2,7 +2,7 @@ require 'test_helper'
 
 class HasPaperTrailModelTest < ActiveSupport::TestCase
 
-  context 'A record' do
+  context 'A record with defined "only" and "ignore" attributes' do
     setup { @article = Article.create }
 
     context 'which updates an ignored column' do
@@ -57,7 +57,15 @@ class HasPaperTrailModelTest < ActiveSupport::TestCase
         end
       end
     end
+  end
 
+  context 'A record with defined "ignore" attribute' do
+    setup { @legacy_widget = LegacyWidget.create }
+
+    context 'which updates an ignored column' do
+      setup { @legacy_widget.update_attributes :version => 1 }
+      should_not_change('the number of versions') { Version.count }
+    end
   end