status/code: return 400 on invalid status code

Request such as `/status/4!9` caused a `ValueError` exception when
trying to cast the status to an int. Now the client is greeted with
`400` and a body of `Invalid status code`.

Fixes #329.

httpbin/core.py

@@ -294,7 +294,10 @@ def view_status_code(codes):
     """Return status code or random status code if more than one are given"""
 
     if ',' not in codes:
-        code = int(codes)
+        try:
+            code = int(codes)
+        except ValueError:
+            return Response('Invalid status code', status=400)
         return status_code(code)
 
     choices = []
@@ -305,7 +308,10 @@ def view_status_code(codes):
         else:
             code, weight = choice.split(':')
 
-        choices.append((int(code), float(weight)))
+        try:
+            choices.append((int(code), float(weight)))
+        except ValueError:
+            return Response('Invalid status code', status=400)
 
     code = weighted_choice(choices)
 

test_httpbin.py

@@ -373,6 +373,14 @@ class HttpbinTestCase(unittest.TestCase):
             response = self.app.open(path='/status/418', method=m)
             self.assertEqual(response.status_code, 418)
 
+    def test_status_endpoint_invalid_code(self):
+        response = self.app.get(path='/status/4!9')
+        self.assertEqual(response.status_code, 400)
+
+    def test_status_endpoint_invalid_codes(self):
+        response = self.app.get(path='/status/200,402,foo')
+        self.assertEqual(response.status_code, 400)
+
     def test_xml_endpoint(self):
         response = self.app.get(path='/xml')
         self.assertEqual(