Test hook registration

spec/premailer-rails3/hook_registration_spec.rb

@@ -0,0 +1,10 @@
+require 'spec_helper'
+
+describe 'ActionMailer::Base.register_interceptor' do
+  it 'should register interceptor PremailerRails::Hook' do
+    ActionMailer::Base
+      .expects(:register_interceptor)
+      .with(PremailerRails::Hook)
+    load 'premailer-rails3.rb'
+  end
+end