diff --git a/lib/rb/spec/struct_spec.rb b/lib/rb/spec/struct_spec.rb
index 8e106fa..e57d555 100644
--- a/lib/rb/spec/struct_spec.rb
+++ b/lib/rb/spec/struct_spec.rb
@@ -36,6 +36,17 @@
     struct.shorts.should == Set.new([5, 17, 239])
   end
 
+  it "should not share default values between instances" do
+    begin
+      struct = Foo.new
+      struct.ints << 17
+      Foo.new.ints.should == [1,2,2,3]
+    ensure
+      # ensure no leakage to other tests
+      Foo::FIELDS[4][:default] = [1,2,2,3]
+    end
+  end
+
   it "should have proper == semantics" do
     Foo.new.should_not == Hello.new
     Foo.new.should == Foo.new