make sure Request.method is always str

scrapy/http/request/__init__.py

@@ -25,7 +25,7 @@ class Request(object_ref):
                  dont_filter=False, errback=None):
 
         self._encoding = encoding  # this one has to be set first
-        self.method = method.upper()
+        self.method = str(method).upper()
         self._set_url(url)
         self._set_body(body)
         self.priority = priority

scrapy/tests/test_http_request.py

@@ -162,6 +162,10 @@ class RequestTest(unittest.TestCase):
         self.assertEqual(r4.meta, {})
         assert r4.dont_filter is False
 
+    def test_method_always_str(self):
+        r = self.request_class("http://www.example.com", method=u"POST")
+        assert isinstance(r.method, str)
+
     def test_weakref_slots(self):
         """Check that classes are using slots and are weak-referenceable"""
         x = self.request_class('http://www.example.com')