add testing

test/integration/canonical/serverspec/canonical_spec.rb

@@ -0,0 +1,23 @@
+# Copyright:: 2012-2017, Chef Software, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+require_relative './spec_helper'
+
+describe file('/etc/postfix/recipient_canonical.db') do
+  it { should be_file }
+end
+
+describe file('/etc/postfix/main.cf') do
+  its(:content) { should match(%r{^\s*recipient_canonical_maps\s*=.*\/etc\/postfix\/recipient_canonical\s*$}) }
+end