diff --git a/test/net/http/test_http.rb b/test/net/http/test_http.rb
index 13d1803aa9..e0c503c288 100644
--- a/test/net/http/test_http.rb
+++ b/test/net/http/test_http.rb
@@ -225,7 +225,7 @@ class TestNetHTTP < Test::Unit::TestCase
     def host.to_str; raise SocketError, "open failure"; end
     uri = Struct.new(:scheme, :hostname, :port).new("http", host, port)
     assert_raise_with_message(SocketError, /#{host}:#{port}/) do
-      Net::HTTP.get(uri)
+      clean_http_proxy_env{ Net::HTTP.get(uri) }
     end
   end