allow testing environment functions

[asharpe]

This is probably the wrong way to achieve the outcome, it's just what I did to get it working and figured it should be shared.

Scenario

As per https://puppet.com/docs/puppet/5.3/functions_ruby_overview.html#location I have an "environment function" named environment::upcase and I want to test it. My test code looks like

require 'spec_helper'

describe 'environment::upcase' do
 it {
   should run.with_params("a").and_return("A")
 }
end

Issue

Running the tests as-is fails with

     NoMethodError:
       undefined method `func_name' for nil:NilClass
     # ./vendor/gems/ruby/gems/rspec-puppet-2.6.11/lib/rspec-puppet/matchers/run.rb:109:in `func_name'
     # ./vendor/gems/ruby/gems/rspec-puppet-2.6.11/lib/rspec-puppet/matchers/run.rb:135:in `failure_message_generic'
     # ./vendor/gems/ruby/gems/rspec-puppet-2.6.11/lib/rspec-puppet/matchers/run.rb:92:in `failure_message'
     # ./spec/functions/environment__upcase_spec.rb:25:in `block (2 levels) in <top (required)>'

Workaround

This MR allows the test to succeed

# bundle exec rspec
....

Finished in 0.51518 seconds (files took 8.41 seconds to load)
1 examples, 0 failures

[coveralls]

Coverage decreased (-1.5%) to 84.551% when pulling 6e15572 on asharpe:environment-functions into 5cc25d0 on rodjek:master.

[DavidS]

Given the pain this is causing to test, and that I see no good reason for environment functions that could not also be addressed by having an environment module for this, I'll bring up the topic of deprecating/removing environment functions with the puppet coremunity team.

Internal ref: https://puppet.slack.com/archives/CF466J67L/p1603713702132700 , https://puppet.slack.com/archives/CF418Q1M2/p1603738590085200

[DavidS]

After tracing through the tickets and code changes, I'm still not 100% clear on the history of "environment functions". The best I could determine is they were probably introduced as a side-effect to loader changes for the Puppet 4 function API (see puppetlabs/puppet#2546 puppetlabs/puppet#5455) and then someone decided to document it.

My suggestion of moving those functions to a module called environment is not workable, since that is a keyword in the puppet language, and thus the module can't be called that.

I'm still having a hard time coming up with a use-case where this capability is useful for a production server/agent setup in a way that couldn't also be addressed by having said functions in a module (even if it is not called "environment"). Therefore I'm still in the camp of "it's not worth jumping through all the hoops for getting the test moons aligned just right".

[scotje]

Bumping this from the 2.8.x release since it sounds like it may just not get implemented.

[logicminds]

I was having a similar issue with a namespace function. It appears that testing a function only works when the function is in a directory with the module name. Which in this case is: <module>/lib/puppet/functions/environment/upcase.rb