Lower the retry interval to 0.0 in tests

This is just to speed up tests, we don't really need to wait. This also
uncovered a bug in the creation of the `StreamStopped` instance, which
was converting `0.0` to `None`.

Signed-off-by: Leandro Lucarella <[email protected]>

Author: llucax

src/frequenz/client/base/streaming.py

@@ -188,7 +188,9 @@ async def _run(self) -> None:
 
             await sender.send(
                 StreamStopped(
-                    retry_time=timedelta(seconds=interval) if interval else None,
+                    retry_time=(
+                        timedelta(seconds=interval) if interval is not None else None
+                    ),
                     exception=error,
                 )
             )

tests/streaming/test_grpc_stream_broadcaster.py

@@ -324,7 +324,7 @@ async def test_messages_on_retry(
             receiver_ready_event,
         ),
         transform=_transformer,
-        retry_strategy=retry.LinearBackoff(limit=1, interval=0.01, jitter=0.0),
+        retry_strategy=retry.LinearBackoff(limit=1, interval=0.0, jitter=0.0),
         retry_on_exhausted_stream=True,
     )
 
@@ -340,7 +340,7 @@ async def test_messages_on_retry(
     assert items == []
     assert events == [
         StreamStarted(),
-        StreamStopped(timedelta(seconds=0.01), error),
+        StreamStopped(timedelta(seconds=0.0), error),
         StreamStarted(),
         StreamStopped(None, error),
         StreamFatalError(error),