diff --git a/sinatra-contrib/lib/sinatra/test_helpers.rb b/sinatra-contrib/lib/sinatra/test_helpers.rb
index 9ec8585d..b75870a6 100644
--- a/sinatra-contrib/lib/sinatra/test_helpers.rb
+++ b/sinatra-contrib/lib/sinatra/test_helpers.rb
@@ -72,7 +72,7 @@ module Sinatra
 
     def session
       return {} unless last_request?
-      raise Rack::Test:Error, "session not enabled for app" unless last_env["rack.session"] or app.session?
+      raise Rack::Test::Error, "session not enabled for app" unless last_env["rack.session"] or app.session?
       last_request.session
     end