Acceptance test RedisCacheStore as a store backend doesn't leak keys

spec/acceptance/stores/redis_cache_store_spec.rb

@@ -1,6 +1,8 @@
 require_relative "../../spec_helper"
 require_relative "../../support/cache_store_helper"
 
+require "timecop"
+
 if ActiveSupport.version >= Gem::Version.new("5.2.0")
   describe "RedisCacheStore as a cache backend" do
     before do
@@ -12,5 +14,28 @@ if ActiveSupport.version >= Gem::Version.new("5.2.0")
     end
 
     it_works_for_cache_backed_features
+
+    it "doesn't leak keys" do
+      Rack::Attack.throttle("by ip", limit: 1, period: 1) do |request|
+        request.ip
+      end
+
+      key = nil
+
+      # Freeze time during these statement to be sure that the key used by rack attack is the same
+      # we pre-calculate in local variable `key`
+      Timecop.freeze do
+        key = "rack::attack:#{Time.now.to_i}:by ip:1.2.3.4"
+
+        # puts key
+        get "/", {}, "REMOTE_ADDR" => "1.2.3.4"
+      end
+
+      assert_equal "1", Rack::Attack.cache.store.fetch(key)
+
+      sleep 2.1
+
+      assert_nil Rack::Attack.cache.store.fetch(key)
+    end
   end
 end