diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 15bbcaeb..2c5889c2 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -55,6 +55,7 @@ def call
         :proxy_port => nil)
     vm_config = double(
       :vm => double('config_vm',
+                    :box => nil,
                     :synced_folders => [],
                     :provisioners => [],
                     :hostname => nil,