Add basic tests for environment functions

Author: rodjek

spec/fixtures/lib/puppet/functions/environment/upcase.rb

@@ -0,0 +1,9 @@
+Puppet::Functions.create_function(:'environment::upcase') do
+  dispatch :up do
+    param 'String', :some_string
+  end
+
+  def up(some_string)
+    some_string.upcase
+  end
+end

spec/functions/environment_upcase_spec.rb

@@ -0,0 +1,5 @@
+require 'spec_helper'
+
+describe 'environment::upcase' do
+  it { should run.with_params('aaa').and_return('AAA') }
+end