Resurrect support of #haml_object_ref

Close #1097

lib/haml/object_ref.rb

@@ -6,7 +6,12 @@ module Haml
         object, prefix = args
         return {} unless object
 
-        suffix = underscore(object.class)
+        suffix =
+          if object.respond_to?(:haml_object_ref)
+            object.haml_object_ref
+          else
+            underscore(object.class)
+          end
         {
           'class' => [prefix, suffix].compact.join('_'),
           'id'    => [prefix, suffix, object.id || 'new'].compact.join('_'),

test/haml/engine_test.rb

@@ -1299,22 +1299,22 @@ HAML
                  render("%p[user] New User", :locals => {:user => user}))
   end
 
-  def test_object_ref_before_attrs; skip # object reference
+  def test_object_ref_before_attrs
     user = User.new 42
     assert_equal("<p class='struct_user' id='struct_user_42' style='width: 100px;'>New User</p>\n",
-                 render("%p[user]{:style => 'width: 100px;'} New User", :locals => {:user => user}))
+                 render_template("%p[user]{:style => 'width: 100px;'} New User", locals: { user: user }))
   end
 
-  def test_object_ref_with_custom_haml_class; skip # object reference
+  def test_object_ref_with_custom_haml_class
     custom = CustomHamlClass.new 42
     assert_equal("<p class='my_thing' id='my_thing_42' style='width: 100px;'>My Thing</p>\n",
-                 render("%p[custom]{:style => 'width: 100px;'} My Thing", :locals => {:custom => custom}))
+                 render_template("%p[custom]{:style => 'width: 100px;'} My Thing", locals: { custom: custom }))
   end
 
-  def test_object_ref_with_multiple_ids; skip # object reference
+  def test_object_ref_with_multiple_ids
     cpk_record = CpkRecord.new([42,6,9])
     assert_equal("<p class='struct_cpk_record' id='struct_cpk_record_42_6_9' style='width: 100px;'>CPK Record</p>\n",
-                 render("%p[cpk_record]{:style => 'width: 100px;'} CPK Record", :locals => {:cpk_record => cpk_record}))
+                 render_template("%p[cpk_record]{:style => 'width: 100px;'} CPK Record", locals: { cpk_record: cpk_record }))
   end
 
   def test_non_literal_attributes

test/test_helper.rb

@@ -58,12 +58,14 @@ class Haml::TestCase < BASE_TEST_CLASS
     eval Haml::Engine.new(options).call(text), scope
   end
 
-  def assert_haml_ugly(text, options = {})
+  def render_template(text, options = {})
     haml_base = { escape_html: true }
     scope  = options.delete(:scope) || Object.new
     locals = options.delete(:locals) || {}
     Haml::Template.new(haml_base.merge(options)) { text }.render(scope, locals)
   end
+  # TODO: fix the usages of assert_haml_ugly
+  alias :assert_haml_ugly :render_template
 
   def assert_warning(message)
     the_real_stderr, $stderr = $stderr, StringIO.new