Write a bunch of code

data/os/Fedora.yaml

+---
+workstation::desktop_environments:
+  - xfce
+  - gnome
+
+workstation::packages:
+  - vlc
+
+workstation::desktop_environment::gnome::packages: [] # Installed by default
+
+workstation::desktop_environment::xfce::packages:
+  - xfce4-panel
+  - xfce4-session
+  - xfce4-settings
+  - xfconf
+  - xfdesktop
+  - xfwm4

manifests/desktop_environment/gnome.pp

+# @summary A short summary of the purpose of this class
+#
+# A description of what this class does
+#
+# @example
+#   include workstation::desktop_environment::gnome
+class workstation::desktop_environment::gnome (
+  $packages = undef,
+){
+  ensure_packages($packages)
+}

manifests/desktop_environment/xfce.pp

+# @summary A short summary of the purpose of this class
+#
+# A description of what this class does
+#
+# @example
+#   include workstation::desktop_environment::xfce
+class workstation::desktop_environment::xfce {
+}

manifests/init.pp

 # Install a generic workstation, all bells and whistles
 
-# Add lysator-specific things to the profile instead.
+# Add lysator-specific things to the profile instead, or via foreman.
 class workstation (
-  $desktop_environments = [],
-  $packages = [],
+  $desktop_environments = undef, # hiera
+  $packages = undef, # hiera
 ){
   # Install and setup a login manager
-  include ::desktop_environment::login_manager
+  include ::workstation::login_manager
 
-  ensure_packages($packages)
+  # Install a desktop environment
   $desktop_environments.each | $e | {
-    include "::desktop_environment::${e}"
+    include "::workstation::desktop_environment::${e}"
   }
 
   # Install additional packages
+  ensure_packages($packages)
 }

manifests/login_manager.pp

+# @summary Setup a login manager
+#
+# @example
+#   include workstation::login_manager
+class workstation::login_manager {
+}

spec/classes/desktop_environment/gnome_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe 'workstation::desktop_environment::gnome' do
+  on_supported_os.each do |os, os_facts|
+    context "on #{os}" do
+      let(:facts) { os_facts }
+
+      it { is_expected.to compile }
+    end
+  end
+end

spec/classes/desktop_environment/xfce_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe 'workstation::desktop_environment::xfce' do
+  on_supported_os.each do |os, os_facts|
+    context "on #{os}" do
+      let(:facts) { os_facts }
+
+      it { is_expected.to compile }
+    end
+  end
+end

spec/classes/login_manager_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe 'workstation::login_manager' do
+  on_supported_os.each do |os, os_facts|
+    context "on #{os}" do
+      let(:facts) { os_facts }
+
+      it { is_expected.to compile }
+    end
+  end
+end