make sure that we only handle hash urls..

casimport/__init__.py

@@ -689,3 +689,7 @@ class Test(unittest.TestCase):
 		# that when read raises an exception
 		with self.assertRaises(ValueError):
 			fdcas.fetch_data(urllib.parse.urlparse('hash://sha256/0000'))
+
+		# that when passed an invalid url
+		with self.assertRaises(ValueError):
+			fdcas.fetch_data(urllib.parse.urlparse('https://sha256/0000'))