Add diff hunks to notification emails on MR

Added diff hunks to notification emails of messages on merge requests. This
provides code context to the note. Uses existing template for formatting
a diff for email (from repository push notifications).

1 files changed, 17 insertions, 2 deletions

diff --git a/spec/mailers/notify_spec.rb b/spec/mailers/notify_spec.rb
index 932a5dc4862..b40a6b1cbac 100644
--- a/spec/mailers/notify_spec.rb
+++ b/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}") }