(MAINT) improve test coverage for future parser

Author: DavidS

spec/functions/type_of_spec.rb

@@ -1,12 +1,6 @@
 require 'spec_helper'
 
-if ENV["FUTURE_PARSER"] == 'yes'
-  describe 'type_of' do
-    pending 'teach rspec-puppet to load future-only functions under 3.7.5'
-  end
-end
-
-if Puppet.version.to_f >= 4.0
+if Puppet.version.to_f >= 4.0 or ENV["FUTURE_PARSER"] == 'yes'
   describe 'type_of' do
     it { is_expected.not_to eq(nil) }
     it { is_expected.to run.with_params().and_raise_error(ArgumentError) }