Changes as requested by @hbuckle

1. Parameterised the install_options method to make testing easier.

2. Added an example in the documentation of how to pass a hash and a switch to the install_options argument

README.md

@@ -188,6 +188,19 @@ file{"C:\Program Files\PackageManagement\ProviderAssemblies\nuget\2.8.5.208\Micr
 
 `puppet-powershellmodule` implements a [package type](http://docs.puppet.com/references/latest/type.html#package) with a resource provider, which is built into Puppet.
 
+The implementation supports the [install_options](https://puppet.com/docs/puppet/6.2/type.html#package-attribute-install_options) attribute which can be used to pass additional options to the PowerShell Install-Modules command, e.g.:
+
+```
+package { 'xPSDesiredStateConfiguration':
+  ensure   => latest,
+  provider => 'windowspowershell',
+  source   => 'PSGallery',
+  install_options => [ '-AllowClobber',
+                       { '-proxy' => 'http://proxy.local.domain' }  ]
+}
+
+```
+
 ### pspackageprovider
 
 #### Properties/Parameters

lib/puppet/provider/package/powershellcore.rb

@@ -55,10 +55,10 @@ def update
   # @param options [Array]
   # @return Concatenated list of options
   # @api private
-  def install_options
-    return unless @resource[:install_options]
+  def install_options(options)
+    return unless options
 
-    @resource[:install_options].collect do |val|
+    options.collect do |val|
       case val
         when Hash
           val.keys.sort.collect do |k|
@@ -88,7 +88,7 @@ def install_command
     command = "Install-Module #{@resource[:name]} -Scope AllUsers -Force"
     command << " -RequiredVersion #{@resource[:ensure]}" unless [:present, :latest].include? @resource[:ensure]
     command << " -Repository #{@resource[:source]}" if @resource[:source]
-    command << " #{install_options}" if @resource[:install_options]
+    command << " #{install_options(@resource[:install_options])}" if @resource[:install_options]
     command
   end
 
@@ -103,7 +103,7 @@ def latest_command
   def update_command
     command = "Install-Module #{@resource[:name]} -Scope AllUsers -Force"
     command << " -Repository #{@resource[:source]}" if @resource[:source]
-    command << " #{install_options}" if @resource[:install_options]
+    command << " #{install_options(@resource[:install_options])}" if @resource[:install_options]
     command
   end
 end