add library method to detect beta

libraries/system.rb

@@ -42,6 +42,10 @@ module MacOS
           shell_out('defaults -currentHost read-type com.apple.screensaver idleTime', user: @user).stdout.chomp == 'Type is integer'
       end
     end
+
+    def beta?
+      node['platform_version'].chars.last.match?(/0/) && node['platform_build'].chars.last.match?(/[[:alpha:]]/)
+    end
   end
 end
 Chef::Resource.include(MacOS::System)

resources/command_line_tools.rb

@@ -3,13 +3,12 @@ unified_mode true
 provides :command_line_tools
 
 property :name, String, default: ''
-property :beta, [true, false], default: false
 property :compile_time, [true, false],
   description: 'Install the Xcode Command Line Tools at compile time.',
   default: false, desired_state: false
 
 action :install do
-  if new_resource.beta
+  if MacOS.beta?
     directory 'create CLT folder' do
       path '/Library/Developer/CommandLineTools'
       recursive true
@@ -42,7 +41,7 @@ action :install do
 end
 
 action :upgrade do
-  if new_resource.beta
+  if MacOS.beta?
     file 'create CLT folder' do
       path '/Library/Developer/CommandLineTools'
       recursive true