Add a puppet_execution_environment hook method

lib/kafo/configuration.rb

@@ -169,8 +169,6 @@ def params_default_values
         execution_env = ExecutionEnvironment.new(self)
         KafoConfigure.exit_handler.register_cleanup_path(execution_env.directory)
 
-        puppetconf = execution_env.configure_puppet('noop' => true)
-
         dump_manifest = <<EOS
           #{includes}
           class { '::kafo_configure::dump_values':
@@ -180,8 +178,8 @@ class { '::kafo_configure::dump_values':
 EOS
 
         @logger.info 'Loading default values from puppet modules...'
-        command = PuppetCommand.new(dump_manifest, [], puppetconf, self).command
-        stdout, stderr, status = Open3.capture3(*PuppetCommand.format_command(command))
+        command = execution_env.build_command(dump_manifest, settings: {'noop' => true})
+        stdout, stderr, status = Open3.capture3(*command)
 
         @logger.debug stdout
         @logger.debug stderr

lib/kafo/execution_environment.rb

@@ -42,6 +42,13 @@ def configure_puppet(settings = {})
       PuppetConfigurer.new(puppet_conf, settings)
     end
 
+    def build_command(code, options: [], settings: {}, use_answers: false)
+      store_answers if use_answers
+      puppetconf = configure_puppet(settings)
+      command = Kafo::PuppetCommand.new(code, options, puppetconf, @config).command
+      Kafo::PuppetCommand.format_command(command)
+    end
+
     private
 
     def environmentpath

lib/kafo/hook_context.rb

@@ -1,3 +1,4 @@
+require 'fileutils'
 require 'kafo/data_type'
 require 'kafo/base_context'
 
@@ -134,5 +135,13 @@ def scenario_path
     def scenario_data
       self.kafo.config.app
     end
+
+    # Yield a Puppet execution environment that's isolated from the system
+    def puppet_execution_environment
+      execution_env = Kafo::ExecutionEnvironment.new(self.kafo.config)
+      yield execution_env
+    ensure
+      FileUtils.rm_rf(execution_env.directory)
+    end
   end
 end

lib/kafo/kafo_configure.rb

@@ -425,14 +425,14 @@ def run_installation
       execution_env = ExecutionEnvironment.new(config)
       self.class.exit_handler.register_cleanup_path(execution_env.directory)
 
-      execution_env.store_answers
-      puppetconf = execution_env.configure_puppet(
+      code = 'include kafo_configure'
+      settings = {
         'color'     => false,
         'evaltrace' => !!@progress_bar,
         'noop'      => !!noop?,
         'profile'   => !!profile?,
         'show_diff' => true,
-      )
+      }
 
       exit_code   = 0
       exit_status = nil
@@ -442,11 +442,11 @@ def run_installation
           '--detailed-exitcodes',
       ]
       begin
-        command = PuppetCommand.new('include kafo_configure', options, puppetconf).command
+        command = execution_env.build_command(code, options: options, settings: settings, use_answers: true)
         log_parser = PuppetLogParser.new
         logger = Logger.new('configure')
 
-        PTY.spawn(*PuppetCommand.format_command(command)) do |stdin, stdout, pid|
+        PTY.spawn(*command) do |stdin, stdout, pid|
           begin
             stdin.each do |line|
               line = normalize_encoding(line)

test/kafo/hook_context_test.rb

@@ -121,5 +121,50 @@ module Kafo
         assert_equal false, context.has_custom_fact?('not_my_custom_fact')
       end
     end
+
+    describe '#puppet_execution_environment' do
+      let(:config) { Minitest::Mock.new }
+      let(:code) {  }
+
+      before do
+        kafo.expect :config, config
+      end
+
+      specify 'creates directory' do
+        context.puppet_execution_environment do |env|
+          assert File.directory?(env.directory)
+        end
+      end
+
+      specify 'deletes directory' do
+        directory = context.puppet_execution_environment do |env|
+          env.directory
+        end
+
+        refute File.directory?(directory)
+      end
+
+      specify 'builds command' do
+        def config.app
+          {}
+        end
+        def config.module_dirs
+          ['./modules']
+        end
+        def config.kafo_modules_dir
+          ['./kafo_modules']
+        end
+        config.expect :scenario_id, 'foobar'
+        config.expect :config_file, 'foobar.yaml'
+
+        context.puppet_execution_environment do |env|
+          result = env.build_command("notice { 'Hello' }")
+          assert_kind_of(Array, result)
+          # TODO: result[0] can either be a Hash or ::ENV which is an Object
+          assert_match(%{notice { 'Hello' }}, result[1])
+          assert_equal({unsetenv_others: false}, result[2])
+        end
+      end
+    end
   end
 end