diff --git a/lib/rspec-puppet/matchers/create_generic.rb b/lib/rspec-puppet/matchers/create_generic.rb
index 3f95904..1835232 100644
--- a/lib/rspec-puppet/matchers/create_generic.rb
+++ b/lib/rspec-puppet/matchers/create_generic.rb
@@ -17,7 +17,7 @@ module RSpec::Puppet
 
       def without(*args, &block)
         params = args.shift
-        @expected_undef_params = (@expected_undef_params || []) | params.to_a
+        @expected_undef_params = (@expected_undef_params || []) | Array(params)
         self
       end