Add diff hunks to notification emails on MR

CHANGELOG.md

@@ -797,6 +797,7 @@ entry.
 ## 8.11.0 (2016-08-22)
 
   - Use test coverage value from the latest successful pipeline in badge. !5862
+  - Add git diff context to notifications of new notes on merge requests !5855 (hoopes)
   - Add test coverage report badge. !5708
   - Remove the http_parser.rb dependency by removing the tinder gem. !5758 (tbalthazar)
   - Add Koding (online IDE) integration

app/views/notify/note_merge_request_email.html.haml

+= content_for :head do
+  = stylesheet_link_tag 'mailers/highlighted_diff_email'
+
 - if @note.diff_note? && @note.diff_file
   %p.details
     New comment on diff for
     = link_to @note.diff_file.file_path, @target_url
     \:
 
+    .diff-content.code.js-syntax-highlight
+      %table
+        - Discussion.new([@note]).truncated_diff_lines.each do |line|
+          = render "projects/diffs/line", line: line, diff_file: @note.diff_file, plain: true
+
 = render 'note_message'

app/views/notify/repository_push_email.html.haml

 = content_for :head do
-  = stylesheet_link_tag 'mailers/repository_push_email'
+  = stylesheet_link_tag 'mailers/highlighted_diff_email'
 
 %h3
   #{@message.author_name} #{@message.action_name} #{@message.ref_type} #{@message.ref_name}

spec/mailers/notify_spec.rb

@@ -580,8 +580,10 @@ describe Notify do
       let(:note_author) { create(:user, name: 'author_name') }
       let(:note) { create(:note, project: project, author: note_author) }
 
-      before :each do
-        allow(Note).to receive(:find).with(note.id).and_return(note)
+      before do |example|
+        unless example.metadata[:skip_before]
+          allow(Note).to receive(:find).with(note.id).and_return(note)
+        end
       end
 
       shared_examples 'a note email' do
@@ -663,6 +665,19 @@ describe Notify do
         end
       end
 
+      describe "on a merge request with diffs", :skip_before do
+        let(:merge_request) { create(:merge_request_with_diffs) }
+        let(:note_with_diff) {create(:diff_note_on_merge_request)}
+
+        before(:each) { allow(note_with_diff).to receive(:noteable).and_return(merge_request) }
+        subject { Notify.note_merge_request_email(recipient.id, note_with_diff.id) }
+
+        it 'includes diffs with character-level highlighting' do
+          expected_line_text = Discussion.new([note_with_diff]).truncated_diff_lines.first.text
+          is_expected.to have_body_text expected_line_text
+        end
+      end
+
       describe 'on an issue' do
         let(:issue) { create(:issue, project: project) }
         let(:note_on_issue_path) { namespace_project_issue_path(project.namespace, project, issue, anchor: "note_#{note.id}") }