diff --git a/spec/tracker/tracker_spec.rb b/spec/tracker/tracker_spec.rb
index 664e6c1..21e8596 100644
--- a/spec/tracker/tracker_spec.rb
+++ b/spec/tracker/tracker_spec.rb
@@ -16,7 +16,7 @@ class BodyHandler < DummyHandler
 RSpec.describe Rack::Tracker do
   def app
     Rack::Builder.new do
-      use Rack::Session::Cookie, secret: "FOO"
+      use Rack::Session::Cookie, secret: "a" * 64
 
       use Rack::Tracker do
         handler DummyHandler, { foo: 'head' }