Add mock raise_for_status().

beanprice/sources/yahoo_test.py

@@ -26,6 +26,10 @@ def __init__(self, contents, status_code=requests.codes.ok):
     def json(self, **kwargs):
         return json.loads(self.contents, **kwargs)
 
+    def raise_for_status(self):
+        if self.status_code != requests.codes.ok:
+            raise HTTPError(self.status_code)
+
 
 class YahooFinancePriceFetcher(unittest.TestCase):