Show tag-based notes on new request preview

Use TaggableTerms to check OutgoingMessage#body for terms that we have a
tag-based Note for.

We can use this to warn users that they’re about to make a mistake.

For example, we could configure OutgoingMessage like so:

    OutgoingMessage.taggable_terms = {
      body: {
        /my 999 call/i => ‘preview_warning_sar’
      }
    }

Then, if a user includes “my 999 call” in their request content, we’d
detect this and render a Note applied via the ‘preview_warning_sar’ tag.

app/controllers/request_controller.rb

@@ -252,6 +252,8 @@ def new
       return
     end
 
+    @outgoing_message.update_taggable_terms
+
     # Show preview page, if it is a preview
     return render_new_preview if params[:preview].to_i == 1
 

app/models/outgoing_message.rb

@@ -29,7 +29,9 @@ class OutgoingMessage < ApplicationRecord
   include MessageProminence
   include Rails.application.routes.url_helpers
   include LinkToHelper
+  include Notable
   include Taggable
+  include TaggableTerms
 
   STATUS_TYPES = %w(ready sent failed).freeze
   MESSAGE_TYPES = %w(initial_request followup).freeze

app/views/request/preview.html.erb

@@ -10,6 +10,8 @@
 
   <div class="message-preview">
     <div class="preview-advice">
+      <%= render_notes(@outgoing_message.all_notes) %>
+
       <div class="advice-panel">
         <ul>
           <li><%= _('Check you haven\'t included any <strong>personal information</strong>.') %></li>

spec/models/outgoing_message_spec.rb

@@ -21,10 +21,14 @@
 require 'spec_helper'
 require 'models/concerns/message_prominence'
 require 'models/concerns/taggable'
+require 'models/concerns/taggable_terms'
 
 RSpec.describe OutgoingMessage do
   it_behaves_like 'concerns/message_prominence', :initial_request
   it_behaves_like 'concerns/taggable', :initial_request
+  it_behaves_like 'concerns/taggable_terms',
+                  :initial_request, { body: 'Some trains and a bus.' },
+                  :body
 
   describe '.is_searchable' do
     subject { described_class.is_searchable }