add acceptance test

spec/acceptance/journal_spec.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+require 'spec_helper_acceptance'
+
+describe 'systemd with remote/upload journal' do
+  machinectl = (fact('os.name') == 'Debian') && %w[11 12].include?(fact('os.release.major')) ? '/bin/machinectl' : '/usr/bin/machinectl'
+
+  context 'configure journal remote/upload' do
+    let(:manifest) do
+      <<~PUPPET
+        class { 'systemd':
+          manage_journal_upload => true,
+          manage_journal_remote => true,
+          journal_upload_settings => {
+            URL => 'http://127.0.0.1',
+          },
+          journal_remote_settings => {},
+        }
+      PUPPET
+    end
+
+    it 'works idempotently with no errors' do
+      apply_manifest(manifest, catch_failures: true)
+      apply_manifest(manifest, catch_changes: true)
+    end
+
+    describe file(machinectl) do
+      it { is_expected.to be_file }
+    end
+  end
+end