diff --git a/test/models/authenticatable_test.rb b/test/models/authenticatable_test.rb
index 61db26e8..9232f910 100644
--- a/test/models/authenticatable_test.rb
+++ b/test/models/authenticatable_test.rb
@@ -8,6 +8,6 @@ class AuthenticatableTest < ActiveSupport::TestCase
   test 'find_first_by_auth_conditions allows custom filtering parameters' do
     user = User.create!(:email => "example@example.com", :password => "123456")
     assert_equal User.find_first_by_auth_conditions({ :email => "example@example.com" }), user
-    assert_nil User.find_first_by_auth_conditions({ :email => "example@example.com" }, :id => user.id.next)
+    assert_nil User.find_first_by_auth_conditions({ :email => "example@example.com" }, :id => user.id.to_s.next)
   end
 end