make sure we check every alternative extension registered for a template engine, fixes #179.

lib/sinatra/base.rb

@@ -508,13 +508,12 @@ module Sinatra
             template.new(path, line.to_i, options) { body }
           else
             found = false
-            path = ::File.join(views, "#{data}.#{engine}")
             Tilt.mappings.each do |ext, klass|
-              break if found = File.exists?(path)
               next unless klass == template
               path = ::File.join(views, "#{data}.#{ext}")
+              break if found = File.exists?(path)
             end
-            throw :layout_missing if eat_errors and !found
+            throw :layout_missing if eat_errors and not found
             template.new(path, 1, options)
           end
         when data.is_a?(Proc) || data.is_a?(String)

test/templates_test.rb

@@ -223,6 +223,12 @@ class TemplatesTest < Test::Unit::TestCase
     end
     assert_equal "Hello <%= 'World' %>!", body
   end
+
+  it "is possible to register another template" do
+    Tilt.register "html.erb", Tilt[:erb]
+    render_app { render :erb, :calc }
+    assert_equal '2', body
+  end
 end
 
 # __END__ : this is not the real end of the script.

test/views/calc.html.erb

@@ -0,0 +1 @@
+<%= 1 + 1 %>