Rails3: model: Member: errors must be set on existing attributes

On Rails 3.0, test fails with following error.

<pre>
Error:
test_validate(MemberTest):
NoMethodError: undefined method `role' for #<Member:0x7f73caf8cd08>
    app/models/member.rb:87:in `validate_role'
    test/unit/member_test.rb:76:in `test_validate'
</pre>

Contributed by Sylvain Utard.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@8124 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/models/member.rb

@@ -84,7 +84,7 @@ class Member < ActiveRecord::Base
   protected
 
   def validate_role
-    errors.add_on_empty :role if member_roles.empty? && roles.empty?
+    errors.add_on_empty :roles if member_roles.empty? && roles.empty?
   end
 
   private

test/unit/member_test.rb

@@ -74,6 +74,7 @@ class MemberTest < ActiveSupport::TestCase
     assert user.save
     member = Member.new(:project_id => 1, :user_id => user.id, :role_ids => [])
     assert !member.save
+    assert_equal I18n.translate('activerecord.errors.messages.empty'), member.errors[:roles].to_s
   end
 
   def test_validate_member_role