diff --git a/core/enumerator/size_spec.rb b/core/enumerator/size_spec.rb
index 4b2beffbb..ac8b9339e 100644
--- a/core/enumerator/size_spec.rb
+++ b/core/enumerator/size_spec.rb
@@ -5,6 +5,10 @@
     Enumerator.new(100) {}.size.should == 100
   end
 
+  it "returns 0 if set size is 0" do
+    Enumerator.new(0) {}.size.should == 0
+  end
+
   it "returns nil if set size is nil" do
     Enumerator.new(nil) {}.size.should == nil
   end