diff --git a/test/fiddle/test_closure.rb b/test/fiddle/test_closure.rb
index 1726db7a78..13dfa5b76e 100644
--- a/test/fiddle/test_closure.rb
+++ b/test/fiddle/test_closure.rb
@@ -83,13 +83,9 @@ module Fiddle
 
     def test_free
       Closure.create(:int, [:void]) do |closure|
-        assert do
-          not closure.freed?
-        end
+        assert_false(closure.freed?)
         closure.free
-        assert do
-          closure.freed?
-        end
+        assert_true(closure.freed?)
         closure.free
       end
     end