(MODULES-3953) add acceptance test for manage_repo param

This commit adds tests to the acceptance test suite in `class_spec.rb` for
confirming that the manage_repo parameter does, in fact, do what it says.
Specifically, we test that puppet created the repo by applying the
'puppet_agent' class with no params (implying default value of true for
`manage_repo`) and then specifically ensuring the repo present with puppet and
catching (failing) on any resultant changes. Then we remove the repo
configuration and apply the puppet agent class again but with `manage_repo =>
false`, and ensure that the repo configs are not re-created (again by catching
changes).

spec/acceptance/class_spec.rb

@@ -39,6 +39,45 @@ class { 'puppet_agent': }
         is_expected.to_not match /parser[ ]*=[ ]*future/
       }
     end
+
+    describe 'manage_repo parameter' do
+      context 'when true (default)' do
+        it 'should create repo config' do
+          pp = "class { 'puppet_agent': }"
+          apply_manifest(pp, :catch_failures => true)
+          case default['platform']
+          when /debian|ubuntu/
+            pp = "include apt\napt::source { 'pc_repo': ensure => present }"
+          when /fedora|el|centos/
+            pp = "yumrepo { 'pc_repo': ensure => present }"
+          else
+            logger.notify("Cannot manage repo on #{default['platform']}, skipping test 'should create repo config'")
+            next
+          end
+          apply_manifest(pp, :catch_changes => true)
+        end
+      end
+
+      context 'when false' do
+        it 'should cease to manage repo config' do
+          pp = "class { 'puppet_agent': }"
+          apply_manifest(pp, :catch_failures => true)
+          case default['platform']
+          when /debian|ubuntu/
+            pp = "include apt\napt::source { 'pc_repo': ensure => absent }"
+          when /fedora|el|centos/
+            pp = "yumrepo { 'pc_repo': ensure => absent }"
+          else
+            logger.notify("Cannot manage repo on #{default['platform']}, skipping test 'should cease to manage repo config'")
+            next
+          end
+          apply_manifest(pp, :catch_failures => true)
+          pp = "class { 'puppet_agent': manage_repo => false }"
+          # expect no changes now that repo is unmanaged
+          apply_manifest(pp, :catch_changes => true)
+        end
+      end
+    end
   end
 
   context 'no services enabled on install' do