Add a helper for comments title

app/helpers/comment_helper.rb

@@ -0,0 +1,7 @@
+module CommentHelper
+  def comment_title_for(comment)
+    (comment.user ? comment.user.username : comment.username) +
+    ' - ' +
+    comment.created_at.strftime('%d/%m/%Y %H:%M')
+  end
+end

app/views/comments/_comment.html.erb

@@ -1,8 +1,6 @@
 <div id="comment_<%= comment.id %>" class="graybox">
   <h2>
-    <%= comment.user ? comment.user : comment.username %>
-    -
-    <%= comment.created_at.strftime('%d/%m/%Y %H:%M') %>
+    <%= comment_title_for comment %>
   </h2>
   <div>
     <%= markdown comment.message %>

spec/helpers/comment_helpers_spec.rb

@@ -0,0 +1,23 @@
+describe CommentHelper do
+  let(:user) { build_stubbed(:user) }
+  let(:comment) { build_stubbed(:comment, created_at: now) }
+  let(:now) { DateTime.now }
+  let(:formatted_now) { now.strftime('%d/%m/%Y %H:%M') }
+
+  describe :comment_title do
+    subject { comment_title_for(comment) }
+
+    context 'when there is a user' do
+      it 'show the title' do
+        comment.user = user
+        should == "#{user.username} - #{formatted_now}"
+      end
+    end
+
+    context 'when there is a username' do
+      it 'show the title with the username' do
+        should == "#{comment.username} - #{formatted_now}"
+      end
+    end
+  end
+end