diff --git a/spec/controllers/groups_controller_spec.rb b/spec/controllers/groups_controller_spec.rb
index d02ce0c1..d1b67fc1 100644
--- a/spec/controllers/groups_controller_spec.rb
+++ b/spec/controllers/groups_controller_spec.rb
@@ -81,7 +81,7 @@
     context "a new own group" do
       before do
         model_attributes[:_founder] = @user.slug
-        model_attributes[:_participants] = [Factory(:user).slug]
+        model_attributes[:_participants] = [Factory(:user).id]
       end
 
       it "should allow creating" do