--- test/test_download.rb	2018-01-22 02:35:45.200017696 +0100
+++ test/test_download.rb.1	2018-01-22 02:38:40.000018113 +0100
@@ -217,8 +217,10 @@
       channel.gets_data "E\n"
       channel.sends_ok
     end
-
-    scp.download!("/path/to/remote", "/path/to/local", :recursive => true, :ssh => { :verbose => :debug })
+    
+    Net::SSH::Test::Extensions::IO.with_test_extension do
+      scp.download!("/path/to/remote", "/path/to/local", :recursive => true, :ssh => { :verbose => :debug })
+    end
     assert_equal "a" * 1234, file.io.string
   end