Integration Testing SMTP With Serverspec

When testing for proper working services it is usually not enough to check whether some port is open and listening and/or some service is up. Checking if your SMTP server is not an open relay is actually as important as having the service up and running.

Fortunately tools exist to allow this kind of testing the easy way.

Serverspec is a great tool to check if your server is properly configured. It is pretty easy to check for listening ports and running services:

postfix_spec.rb

require 'spec_helper'

describe package('postfix') do
  it { should be_installed }
end

describe service('postfix') do
  it { should be_enabled   }
  it { should be_running   }
end

describe port(25) do
  it { should be_listening }
end

The first describe block checks that postfix is installed, the second verifies that is up and running and the third checks if the port 25 is listening. Easy uh?

But if you need to check (and you do!) that your server is not an open relay, or if it has a proper SSL/TLS configuration you need to talk some SMTP to him.

Fortunately Serverspec is running on top of RSpec so we can add ruby code and use some gems to enhance our tests.

Testing SMTP with RSpec and Pony

Many gems exists to send email but pony is lean and does the job. We can add this to our spec:

postfix_spec.rb

describe "Smtp" do

      Pony.options = {
              :to => 'mytest@maildomain.com',
              :from => 'mytest@maildomain.com',
              :subject => 'Test from Serverspec',
              :body => 'Test from Serverspec',
              :via => :smtp,
              :via_options => {
                      :address => 'mail.maildomain.com',
                      :port => '25',
                      :enable_starttls_auto => false,
                      :user_name => 'myusername',
                      :password => 'mypassword',
                      :authentication => :plain,
                      :domain => 'maildomain.com'
              }
      }

      it "should allow sending a mail" do
              expect { Pony.mail({}) }.to be_true
      end

      it "should disallow sending mail on wrong password" do
              old_options = Pony.options
              Pony.options[:via_options][:password] = 'falsepass'
              expect { Pony.mail({}) }.to raise_error
              Pony.options = old_options
      end
end

That’s it! You now can check for Pony to pass or fail any test you want.

Some ideas for further testing:

Check for open relay
Check for proper SSL certificate
Check for sending quotas

Have fun!

@jaguerra

Integration Testing SMTP With Serverspec

Testing SMTP with RSpec and Pony

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