Allow the use of an ensure_absent_val param

This commit aims to add a new feature for the ini_setting provider, this
feature aims to simulate the ensure => absent behavior when a specific
keyword is specified.

Currently a pattern we have is

if $myvar {
  keystone_config { 'SECTION/setting' : value => $myvar }
} else {
  keystone_config { 'SECTION/setting' : ensure => absent }
}

If one has dozens or hundreds of parameters to handle then it can easily
make the manifest hard to read.

The solution offer here would turn the above example in something like

Keystone_config {
  ensure_absent_val = '<SERVICE DEFAULT>' # It is the default
}

keystone_config { 'SECTION/setting' : value => $myvar }

If `$myvar` is '<SERVICE DEFAULT>' then it will act as if `ensure => absent` would
have been specified.

Also added new tests for openstack_config provider

Co-Authored-By: Denis Egorenko <degorenko@mirantis.com>

Change-Id: I0eeebde3aac2662cc7e69bfad7f8d2481463a218

lib/puppet/provider/openstack_config/ini_setting.rb

@@ -1,11 +1,15 @@
-$LOAD_PATH.unshift(File.join(File.dirname(__FILE__),"..","..",".."))
-require 'puppet_x/openstack/util/ini_file'
-
 Puppet::Type.type(:openstack_config).provide(
   :ini_setting,
   :parent => Puppet::Type.type(:ini_setting).provider(:ruby)
 ) do
 
+  def exists?
+    if resource[:value] == ensure_absent_val
+      resource[:ensure] = :absent
+    end
+    super
+  end
+
   def section
     resource[:name].split('/', 2).first
   end
@@ -14,6 +18,10 @@ Puppet::Type.type(:openstack_config).provide(
     resource[:name].split('/', 2).last
   end
 
+  def ensure_absent_val
+    resource[:ensure_absent_val]
+  end
+
   def separator
     '='
   end
@@ -22,9 +30,4 @@ Puppet::Type.type(:openstack_config).provide(
     self.class.file_path
   end
 
-  private
-  def ini_file
-    @ini_file ||= PuppetX::Openstack::Util::IniFile.new(file_path, separator, section_prefix, section_suffix)
-  end
-
 end

lib/puppet_x/openstack/util/ini_file.rb

@@ -1,12 +0,0 @@
-require File.expand_path('../../../../../../inifile/lib/puppet/util/ini_file', __FILE__)
-
-module PuppetX
-  module Openstack
-    module Util
-      class IniFile < Puppet::Util::IniFile
-
-      end
-    end
-  end
-end
-

spec/unit/provider/openstack_config/ini_setting_spec.rb

@@ -0,0 +1,69 @@
+#
+# these tests are a little concerning b/c they are hacking around the
+# modulepath, so these tests will not catch issues that may eventually arise
+# related to loading these plugins.
+# I could not, for the life of me, figure out how to programatcally set the modulepath
+$LOAD_PATH.push(
+  File.join(
+    File.dirname(__FILE__),
+    '..',
+    '..',
+    '..',
+    'fixtures',
+    'modules',
+    'inifile',
+    'lib')
+)
+require 'spec_helper'
+provider_class = Puppet::Type.type(:openstack_config).provider(:ini_setting)
+describe provider_class do
+
+  let(:properties) do
+    {
+      :name              => 'DEFAUL/foo',
+      :value             => 'bar',
+      :ensure_absent_val => 'some_value',
+      :ensure            => :present,
+    }
+  end
+
+  let(:type) do
+    Puppet::Type.newtype(:test_config) do
+      newparam(:name, :namevar => true)
+      newparam(:ensure)
+      newproperty(:value)
+      newparam(:ensure_absent_val)
+    end
+  end
+
+  let(:resource) do
+    resource = type.new(properties)
+    resource
+  end
+
+  context '#exists?' do
+    it 'ensure to present' do
+      child_conf = Class.new(provider_class) do
+          def self.file_path
+            '/some/file/path'
+          end
+      end
+      provider = child_conf.new(resource)
+      provider.exists?
+      expect(resource[:ensure]).to eq :present
+    end
+
+    it 'ensure to absent' do
+      child_conf = Class.new(provider_class) do
+          def self.file_path
+            '/some/file/path'
+          end
+      end
+      provider = child_conf.new(resource)
+      resource[:ensure_absent_val] = 'bar'
+      provider.exists?
+      expect(resource[:ensure]).to eq :absent
+    end
+  end
+
+end