diff --git a/spec/unit/module_tool/tar/gnu_spec.rb b/spec/unit/module_tool/tar/gnu_spec.rb
index 81c519634..79a84d727 100644
--- a/spec/unit/module_tool/tar/gnu_spec.rb
+++ b/spec/unit/module_tool/tar/gnu_spec.rb
@@ -1,23 +1,23 @@
 require 'spec_helper'
 require 'puppet/module_tool'
 
 describe Puppet::ModuleTool::Tar::Gnu do
   let(:sourcefile) { '/space path/the/module.tar.gz' }
   let(:destdir)    { '/space path/the/dest/dir' }
   let(:sourcedir)  { '/space path/the/src/dir' }
   let(:destfile)   { '/space path/the/dest/file.tar.gz' }
 
   it "unpacks a tar file" do
     Dir.expects(:chdir).with(File.expand_path(destdir)).yields(mock)
-    Puppet::Util::Execution.expects(:execute).with("gzip -dc #{Shellwords.shellescape(sourcefile)} | tar xof -")
+    Puppet::Util::Execution.expects(:execute).with("gzip -dc #{Shellwords.shellescape(File.expand_path(sourcefile))} | tar xof -")
     Puppet::Util::Execution.expects(:execute).with("find . -type d -exec chmod 755 {} +")
     Puppet::Util::Execution.expects(:execute).with("find . -type f -exec chmod a-wst {} +")
     Puppet::Util::Execution.expects(:execute).with("chown -R <owner:group> .")
     subject.unpack(sourcefile, destdir, '<owner:group>')
   end
 
   it "packs a tar file" do
     Puppet::Util::Execution.expects(:execute).with("tar cf - #{sourcedir} | gzip -c > #{File.basename(destfile)}")
     subject.pack(sourcedir, destfile)
   end
 end