diff --git a/spec/install/gems/compact_index_spec.rb b/spec/install/gems/compact_index_spec.rb
index 228d8ddcc9b..001118b5133 100644
--- a/spec/install/gems/compact_index_spec.rb
+++ b/spec/install/gems/compact_index_spec.rb
@@ -738,4 +738,12 @@ def start
       G
     end
   end
+
+  it "works when cache dir is world-writable" do
+    install_gemfile! <<-G, :artifice => "compact_index"
+      File.umask(0000)
+      source "#{source_uri}"
+      gem "rack"
+    G
+  end
 end