diff --git a/test/test_helper.rb b/test/test_helper.rb
index 64bbd00c6..9a045f66f 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -29,6 +29,7 @@ def stub_module(name)
 stub_module("FTP")
 stub_module("HTTP")
 stub_module("NtpClient")
+stub_module("InstFunctions")
 
 if ENV["COVERAGE"]
   require "simplecov"