added urlfilter spidermw test

scrapy/tests/test_spidermiddleware_urlfilter.py

+from unittest import TestCase
+
+from scrapy.contrib.spidermiddleware.urlfilter import UrlFilterMiddleware
+from scrapy.http import Response, Request
+from scrapy.spider import BaseSpider
+from scrapy.utils.url import canonicalize_url
+
+
+class TestUrlFilterMiddleware(TestCase):
+
+    def setUp(self):
+        self.spider = BaseSpider()
+        self.mw = UrlFilterMiddleware()
+
+    def test_process_spider_output(self):
+        res = Response('http://scrapytest.org')
+        req_url = 'http://scrapytest.org/?last=1&first=2'
+        reqs = [Request(req_url)]
+
+        out = list(self.mw.process_spider_output(res, reqs, self.spider))
+        self.assertEquals(out[0].url, canonicalize_url(req_url))
+