Implement acceptance tests for webhook-go

cherry-picked from https://github.com/voxpupuli/puppet-r10k/pull/607/files

spec/acceptance/r10k_webhook_spec.rb

@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+require 'spec_helper_acceptance'
+
+describe 'r10k::webhook tests' do
+  context 'when defaults used' do
+    it 'applies' do
+      pp = <<-MANIFEST
+        class { 'r10k': }
+        -> class { 'r10k::webhook': }
+      MANIFEST
+
+      apply_manifest(pp, catch_failures: true)
+      apply_manifest(pp, catch_changes: true)
+    end
+
+    describe package('webhook-go') do
+      it { is_expected.to be_installed }
+    end
+
+    describe file('/etc/voxpupuli/webhook.yml') do
+      it 'exists and has content' do
+        expect(subject).to exist
+        expect(subject).to be_owned_by 'root'
+        expect(subject).to be_grouped_into 'root'
+        expect(subject).to contain "---\nserver:\n  protected: true\n  user: puppet\n  password: puppet\n"
+      end
+    end
+
+    describe service('webhook-go') do
+      it { is_expected.to be_enabled }
+      it { is_expected.to be_running }
+    end
+  end
+end