diff --git a/spec/ruby/core/thread/join_spec.rb b/spec/ruby/core/thread/join_spec.rb
index 6477e17b6e..06e9049808 100644
--- a/spec/ruby/core/thread/join_spec.rb
+++ b/spec/ruby/core/thread/join_spec.rb
@@ -22,10 +22,11 @@ describe "Thread#join" do
   end
 
   it "raises TypeError if the argument is not a valid timeout" do
-    t = Thread.new {sleep}
+    t = Thread.new { sleep }
     -> { t.join(:foo) }.should raise_error TypeError
     -> { t.join("bar") }.should raise_error TypeError
     t.kill
+    t.join
   end
 
   it "returns nil if it is not finished when given a timeout" do