get '/' should match even if PATH_INFO is empty. This fixes compatibility with Rails 3.

Signed-off-by: Simon Rozet <simon@rozet.name>

lib/sinatra/base.rb

@@ -466,7 +466,9 @@ module Sinatra
     def route!(base=self.class, pass_block=nil)
       if routes = base.routes[@request.request_method]
         original_params = @params
-        path            = unescape(@request.path_info)
+
+        path = unescape(@request.path_info)
+        path = "/" if path.empty?
 
         routes.each do |pattern, keys, conditions, block|
           if match = pattern.match(path)

test/routing_test.rb

@@ -84,6 +84,18 @@ class RoutingTest < Test::Unit::TestCase
     assert_equal "<h1>Not Found</h1>", response.body
   end
 
+  it 'matches empty PATH_INFO to "/"' do
+    mock_app {
+      get '/' do
+        'worked'
+      end
+    }
+
+    get '/', {}, "PATH_INFO" => ""
+    assert ok?
+    assert_equal 'worked', body
+  end
+
   it 'takes multiple definitions of a route' do
     mock_app {
       user_agent(/Foo/)