http://blog.segment7.net/articles/2006/09/08/render_tree-for-rails en-us 40 The Blog <p>Spelunking deep in unfamiliar Rails view code? Flushing out the cobwebs and updating your code? Don't know what gets rendered when? <p>I have a solution for you: <pre><code>class ActionView::Base alias plain_render render RENDERS = [:partial, :template, :file, :action, :text, :inline, :nothing, :update] def render(*args) @level ||= 0 print ' ' * @level case args.first when String then p args.first when Hash then hash = args.first found = hash.keys & RENDERS if found.length == 1 then puts "%p => %p" % [found.first, hash[found.first]] else raise "Dunno: %p" % [hash] end else raise "Dunno: %p" % [args] end @level += 1 result = plain_render(*args) @level -= 1 result end end</pre></code> <p>Drop that in <tt>test/render_tree.rb</tt> and require it in your tests when you want to see a tree like this: <pre><samp>$ ruby test/views/things_view_test.rb -n test_view Loaded suite test/views/things_view_test Started "things/things-header" "things/sidebar" "widgets/forms/goal_form" :partial => "widgets/sidenav_boxes/invite_and_edit" "widgets/sidenav_boxes/_invite_and_edit" :partial => "widgets/forms/edit_worth_doing_form" "widgets/forms/_edit_worth_doing_form" :partial => "widgets/sidenav_boxes/tags" "widgets/sidenav_boxes/_tags" :partial => "widgets/sidenav_boxes/popular_places" "widgets/sidenav_boxes/_popular_places" :partial => "widgets/sidenav_boxes/google_ads" "widgets/sidenav_boxes/_google_ads" :partial => "widgets/sidenav_boxes/find_help" "widgets/sidenav_boxes/_find_help" :partial => "widgets/sidenav_boxes/people_who_reached_this_goal" "widgets/sidenav_boxes/_people_who_reached_this_goal" :partial => "widgets/sidenav_boxes/quotation" "widgets/sidenav_boxes/_quotation" :partial => "widgets/sidenav_boxes/goal_created_by" "widgets/sidenav_boxes/_goal_created_by" "widgets/general/post_add_messages" "things/shared_body" :partial => "widgets/goals_gallery_teaser" "widgets/_goals_gallery_teaser" :partial => "entries_bucket" "things/_entries_bucket" "widgets/forms/related_goals" . Finished in 1.205494 seconds. 1 tests, 7 assertions, 0 failures, 0 errors</samp></pre> <p>(I think I'll end up throwing this into ZenTest.) Fri, 08 Sep 2006 11:02:00 -0700 urn:uuid:0663309c-ce6f-412c-a6aa-a8df0160f8e0 drbrain@segment7.net (Eric Hodel) http://blog.segment7.net/articles/2006/09/08/render_tree-for-rails Hacking Rails Toys <p>I&#8217;m entirely happy if you just do the assertion :-}</p> Mon, 11 Sep 2006 12:59:35 -0700 urn:uuid:87a1cb55-4327-4afc-8946-51aebc8741d6 http://blog.segment7.net/articles/2006/09/08/render_tree-for-rails#comment-343 <p>@Michael: I&#8217;m certainly not going to write it, sounds too complicated to me. :) I&#8217;ll just add it as a debugging tool.</p> Mon, 11 Sep 2006 10:47:16 -0700 urn:uuid:c656eee9-bcb4-4b39-99db-2a1488783a7d http://blog.segment7.net/articles/2006/09/08/render_tree-for-rails#comment-342 <p>If you add it to ZenTest, how about making it into an assertion? Something like matching a structural regular expression on renderings</p> <pre> assert_render_tree ['root_template', { :partial =&gt; 'child1', :count =&gt; 3 }, [ { :partial =&gt; 'child2' }, &lt;grand_children&gt; ], &lt;more_children&gt;], render_something </pre> <p>Don&#8217;t make me write a BNF for it&#8230;</p> Mon, 11 Sep 2006 02:16:34 -0700 urn:uuid:e119101d-cb10-4195-80f1-6ad7885c840f http://blog.segment7.net/articles/2006/09/08/render_tree-for-rails#comment-341 <p>Very nice&#8212;trying it out now. Thanks!</p> Fri, 08 Sep 2006 13:17:14 -0700 urn:uuid:3a8da054-bd9d-4cae-b6dc-41430356ccd5 http://blog.segment7.net/articles/2006/09/08/render_tree-for-rails#comment-339