[ServiceBus] mode (ReceiveMode) parameter needs better exception beha…

…vior (#13531)

* mode parameter needs better exception behavior, as if it is mis-typed now it will return an AttributeError further down the stack without useful guidance (and only does so when creating the handler, as well).  Will now return a TypeError at initialization.
* Add note of AttributeError->TypeError behavior for receive_mode misalignment to changelog.

sdk/servicebus/azure-servicebus/CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## 7.0.0b7 (Unreleased)
 
+**Breaking Changes**
+* Passing any type other than `ReceiveMode` as parameter `receive_mode` now throws a `TypeError` instead of `AttributeError`.
 
 ## 7.0.0b6 (2020-09-10)
 

sdk/servicebus/azure-servicebus/azure/servicebus/_common/receiver_mixins.py

@@ -33,6 +33,10 @@ def _populate_attributes(self, **kwargs):
         self._auth_uri = "sb://{}/{}".format(self.fully_qualified_namespace, self.entity_path)
         self._entity_uri = "amqps://{}/{}".format(self.fully_qualified_namespace, self.entity_path)
         self._receive_mode = kwargs.get("receive_mode", ReceiveMode.PeekLock)
+        # While we try to leave failures to the service, in this case the errors lower down the stack are less clear.
+        if not isinstance(self._receive_mode, ReceiveMode):
+            raise TypeError("Parameter 'receive_mode' must be of type ReceiveMode")
+
         self._error_policy = _ServiceBusErrorPolicy(
             max_retries=self._config.retry_total
         )

sdk/servicebus/azure-servicebus/tests/test_queues.py

@@ -1857,11 +1857,12 @@ def test_queue_receiver_invalid_mode(self, servicebus_namespace_connection_strin
 
         with ServiceBusClient.from_connection_string(
             servicebus_namespace_connection_string, logging_enable=False) as sb_client:
-#            with pytest.raises(StopIteration):
-            with sb_client.get_queue_receiver(servicebus_queue.name, 
-                                              max_wait_time="oij") as receiver:
-
-                assert receiver
+            with pytest.raises(TypeError):
+                with sb_client.get_queue_receiver(servicebus_queue.name, 
+                                                  receive_mode=2) as receiver:
+
+                    raise Exception("Should not get here, should fail fast.")
+
 
     @pytest.mark.liveTest
     @pytest.mark.live_test_only