administrator_user = create(:administrator_user)

post :delete, :params => { :display_name => administrator_user.display_name, :id => public_trace_file.id }, :session => { :user => administrator_user }
assert_response :redirect
assert_redirected_to :action => :list, :display_name => administrator_user.display_name
trace = Trace.find(public_trace_file.id)
assert_equal false, trace.visible