Payload sender unit test (#1666)

* payload receiver unit test

* senderTest

* disconnect

* fixWarning

Co-authored-by: Axel Suarez <axsuarez@microsoft.com>

Author: msomanathan

libraries/botbuilder-streaming/tests/test_payload_sender.py

@@ -0,0 +1,56 @@
+from asyncio import Semaphore
+from typing import List
+from uuid import UUID, uuid4
+
+import aiounittest
+from botbuilder.streaming.payload_transport import PayloadSender
+from botbuilder.streaming.payloads import HeaderSerializer
+from botbuilder.streaming.payloads.models import Header
+from botbuilder.streaming.transport import TransportSenderBase
+
+
+class MockTransportSender(TransportSenderBase):
+    def __init__(self):
+        super().__init__()
+        self.send_called = Semaphore(0)
+
+    async def send(self, buffer: List[int], offset: int, count: int) -> int:
+        # Assert
+        if count == 48:  # Header
+            print("Validating Header...")
+            header = HeaderSerializer.deserialize(buffer, offset, count)
+            assert header.type == "A"
+            assert header.payload_length == 3
+            assert header.end
+        else:  # Payload
+            print("Validating Payload...")
+            assert count == 3
+            self.send_called.release()
+
+        return count
+
+    def close(self):
+        pass
+
+
+class TestPayloadSender(aiounittest.AsyncTestCase):
+    async def test_send(self):
+        # Arrange
+        sut = PayloadSender()
+        sender = MockTransportSender()
+        sut.connect(sender)
+
+        headerId: UUID = uuid4()
+        header = Header(type="A", id=headerId, end=True)
+        header.payload_length = 3
+        payload = [1, 2, 3]
+
+        async def mock_sent_callback(h: Header):
+            print(f"{h.type}.{h.payload_length}.{h.id}.{h.end}")
+
+        # Act
+        sut.send_payload(header, payload, is_length_known=True, sent_callback=mock_sent_callback)
+
+        # Assert
+        await sender.send_called.acquire()
+        await sut.disconnect()