2 files changed, 10 insertions, 5 deletions
diff --git a/test/mkmf/base.rb b/test/mkmf/base.rb
index b4cf4884fa..0a75744721 100644
--- a/test/mkmf/base.rb
+++ b/test/mkmf/base.rb
@@ -9,15 +9,22 @@ RbConfig::CONFIG["cppflags"] << " -I."
 CONFIG["cppflags"] << " -I."
 $extout_prefix = "$(extout)$(target_prefix)/"
 
-module TestMkmf
+class TestMkmf < Test::Unit::TestCase
   def setup
     @tmpdir = Dir.mktmpdir
     @curdir = Dir.pwd
     @mkmfobj = Object.new
     Dir.chdir(@tmpdir)
+    class << (@output = "")
+      def flush; end
+      def reopen(*) end
+      alias write <<
+    end
+    $stdout = @output
   end
 
   def teardown
+    $stdout = STDOUT
     Dir.chdir(@curdir)
     FileUtils.rm_rf(@tmpdir)
   end
diff --git a/test/mkmf/test_sizeof.rb b/test/mkmf/test_sizeof.rb
index 29a5253418..e1c498dc0a 100644
--- a/test/mkmf/test_sizeof.rb
+++ b/test/mkmf/test_sizeof.rb
@@ -1,9 +1,7 @@
 require_relative 'base'
 
-module TestMkmf
-  class TestSizeof < Test::Unit::TestCase
-    include TestMkmf
-
+class TestMkmf
+  class TestSizeof < TestMkmf
     def test_sizeof
       open("confdefs.h", "w") {|f|
         f.puts "typedef struct {char x;} test1_t;"