diff --git a/spec/ruby/library/yaml/to_yaml_spec.rb b/spec/ruby/library/yaml/to_yaml_spec.rb
index d73ae9bee4..8e80b02cb4 100644
--- a/spec/ruby/library/yaml/to_yaml_spec.rb
+++ b/spec/ruby/library/yaml/to_yaml_spec.rb
@@ -73,7 +73,7 @@ describe "Object#to_yaml" do
   end
 
   it "returns the YAML representation of a Error object" do
-    StandardError.new("foobar").to_yaml.should match_yaml("--- !ruby/exception:StandardError\nmessage: foobar\n")
+    StandardError.new("foobar").to_yaml.should match_yaml("--- !ruby/exception:StandardError\nmessage: foobar\nbacktrace: \n")
   end
 
   it "returns the YAML representation for Range objects" do