diff --git a/spec/acceptance/concat_spec.rb b/spec/acceptance/concat_spec.rb
index c5c972774..ad959cb34 100644
--- a/spec/acceptance/concat_spec.rb
+++ b/spec/acceptance/concat_spec.rb
@@ -6,11 +6,17 @@
     groupname = 'system'
     scriptname = 'concatfragments.rb'
     vardir = default['puppetvardir']
+    if vardir == ''
+      vardir = '/opt/puppetlabs/puppet/cache'
+    end
   when 'Darwin'
     username = 'root'
     groupname = 'wheel'
     scriptname = 'concatfragments.rb'
     vardir = default['puppetvardir']
+    if vardir == ''
+      vardir = '/opt/puppetlabs/puppet/cache'
+    end
   when 'windows'
     username = 'Administrator'
     groupname = 'Administrators'
@@ -22,11 +28,17 @@
     groupname = 'root'
     scriptname = 'concatfragments.rb'
     vardir = default['puppetvardir']
+    if vardir == ''
+      vardir = '/opt/puppetlabs/puppet/cache'
+    end
   else
     username = 'root'
     groupname = 'root'
     scriptname = 'concatfragments.rb'
     vardir = default['puppetvardir']
+    if vardir == ''
+      vardir = '/opt/puppetlabs/puppet/cache'
+    end
 end
 
 describe 'basic concat test' do