Fix handling of None in allowed_domains.

Nones in allowed_domains ought to be ignored and there are also tests
for that scenario. This commit fixes the handling of None and also the
accompanying tests which are now executed again.

scrapy/spidermiddlewares/offsite.py

@@ -54,12 +54,16 @@ class OffsiteMiddleware(object):
         if not allowed_domains:
             return re.compile('')  # allow all by default
         url_pattern = re.compile("^https?://.*$")
+        domains = []
         for domain in allowed_domains:
-            if url_pattern.match(domain):
+            if domain is None:
+                continue
+            elif url_pattern.match(domain):
                 message = ("allowed_domains accepts only domains, not URLs. "
                            "Ignoring URL entry %s in allowed_domains." % domain)
                 warnings.warn(message, URLWarning)
-        domains = [re.escape(d) for d in allowed_domains if d is not None]
+            else:
+                domains.append(re.escape(domain))
         regex = r'^(.*\.)?(%s)$' % '|'.join(domains)
         return re.compile(regex)
 

tests/test_spidermiddleware_offsite.py

@@ -55,21 +55,21 @@ class TestOffsiteMiddleware2(TestOffsiteMiddleware):
 
 class TestOffsiteMiddleware3(TestOffsiteMiddleware2):
 
-    def _get_spider(self):
-        return Spider('foo')
+    def _get_spiderargs(self):
+        return dict(name='foo')
 
 
 class TestOffsiteMiddleware4(TestOffsiteMiddleware3):
 
-    def _get_spider(self):
-      bad_hostname = urlparse('http:////scrapytest.org').hostname
-      return dict(name='foo', allowed_domains=['scrapytest.org', None, bad_hostname])
+    def _get_spiderargs(self):
+        bad_hostname = urlparse('http:////scrapytest.org').hostname
+        return dict(name='foo', allowed_domains=['scrapytest.org', None, bad_hostname])
 
     def test_process_spider_output(self):
-      res = Response('http://scrapytest.org')
-      reqs = [Request('http://scrapytest.org/1')]
-      out = list(self.mw.process_spider_output(res, reqs, self.spider))
-      self.assertEqual(out, reqs)
+        res = Response('http://scrapytest.org')
+        reqs = [Request('http://scrapytest.org/1')]
+        out = list(self.mw.process_spider_output(res, reqs, self.spider))
+        self.assertEqual(out, reqs)
 
 
 class TestOffsiteMiddleware5(TestOffsiteMiddleware4):