diff --git a/lib/jasmine/headless/cacheable_action.rb b/lib/jasmine/headless/cacheable_action.rb
index 1b7e474..77c57c2 100644
--- a/lib/jasmine/headless/cacheable_action.rb
+++ b/lib/jasmine/headless/cacheable_action.rb
@@ -1,3 +1,5 @@
+require 'digest/sha1'
+
 module Jasmine::Headless
   class CacheableAction
     class << self