Add test for Version's custom timestamps.

test/test_helper.rb

@@ -38,6 +38,7 @@ def change_schema
   ActiveRecord::Migration.verbose = false
   ActiveRecord::Schema.define do
     remove_column :widgets, :sacrificial_column
+    add_column :versions, :custom_created_at, :datetime
   end
   ActiveRecord::Migration.verbose = true
 end

test/unit/timestamp_test.rb

@@ -0,0 +1,39 @@
+require 'test_helper'
+
+class TimestampTest < ActiveSupport::TestCase
+
+  setup do
+    PaperTrail.config.timestamp_field = :custom_created_at
+    change_schema
+    Version.reset_column_information
+
+    Fluxor.instance_eval <<-END
+      has_paper_trail
+    END
+
+    @fluxor = Fluxor.create :name => 'Some text.'
+    @fluxor.update_attributes :name => 'Some more text.'
+    @fluxor.update_attributes :name => 'Even more text.'
+  end
+
+  test 'versions works with custom timestamp field' do
+    # Normal behaviour
+    assert_equal 3, @fluxor.versions.length
+    assert_nil @fluxor.versions[0].reify
+    assert_equal 'Some text.', @fluxor.versions[1].reify.name
+    assert_equal 'Some more text.', @fluxor.versions[2].reify.name
+
+    # Tinker with custom timestamps.
+    now = Time.now.utc
+    @fluxor.versions.reverse.each_with_index do |version, index|
+      version.update_attribute :custom_created_at, (now + index.seconds)
+    end
+
+    # Test we are ordering by custom timestamps.
+    @fluxor.versions true  # reload association
+    assert_nil @fluxor.versions[2].reify
+    assert_equal 'Some text.', @fluxor.versions[1].reify.name
+    assert_equal 'Some more text.', @fluxor.versions[0].reify.name
+  end
+
+end