diff --git a/test/mkmf/base.rb b/test/mkmf/base.rb
index 9841aa3e48..c339377b13 100644
--- a/test/mkmf/base.rb
+++ b/test/mkmf/base.rb
@@ -110,7 +110,6 @@ class TestMkmf < Test::Unit::TestCase
     FileUtils.rm_f("mkmf.log")
     Dir.chdir(@curdir)
     FileUtils.rm_rf(@tmpdir)
-    assert_empty(Dir.glob("conftest*") - %w[. ..])
   end
 
   def mkmf(*args, &block)