Fix comment cancel button url (#1508)

app/views/comments/_form.html.erb

@@ -45,9 +45,9 @@
     <input class="uploaded-image" id="uploaded-image-main" />
   </div>
   <div class="actions" id="submit-wrapper">
-    <a href="<%=commentable.path%>">
-        <button id="cancel-button" class="comment-action-button comment-action-cancel">CANCEL</button>
-    </a>
+    <%= link_to request.referer.present? ? :back : commentable.path do %>
+      <button id="cancel-button" class="comment-action-button comment-action-cancel">CANCEL</button>
+    <% end %>
     <button id="preview-button" class="comment-action-button comment-action-preview">PREVIEW</button>
     <%= f.submit "SUBMIT", id: "submit-button", onclick:"validateField(event)", class:"comment-action-button" %>
   </div>

spec/features/comments/user_edits_a_comment_spec.rb

@@ -4,9 +4,9 @@ RSpec.describe "Editing A Comment", type: :feature, js: true do
   let(:user) { create(:user) }
   let!(:article) { create(:article, show_comments: true) }
   let(:new_comment_text) { Faker::Lorem.paragraph }
+  let!(:comment) { create(:comment, commentable: article, user: user, body_markdown: Faker::Lorem.paragraph) }
 
   before do
-    comment = create(:comment, commentable: article, user: user, body_markdown: Faker::Lorem.paragraph)
     Notification.send_new_comment_notifications(comment)
     sign_in user
   end
@@ -34,4 +34,12 @@ RSpec.describe "Editing A Comment", type: :feature, js: true do
       assert_updated
     end
   end
+
+  context "when user edits via direct path (no referer)" do
+    it "cancels to the article page" do
+      user.reload
+      visit "#{comment.path}/edit"
+      expect(page).to have_link("CANCEL", href: article.path.to_s)
+    end
+  end
 end