diff --git a/pyproject.toml b/pyproject.toml
index 4ac6216b..e204b2b2 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -103,8 +103,8 @@ dev-pytest = [
   "pytest-mock == 3.14.1",
   "pytest-asyncio == 1.1.0",
   "async-solipsism == 0.8",
-  "time-machine == 2.16.0",
-  "hypothesis == 6.136.8",
+  "time-machine == 2.19.0",
+  "hypothesis == 6.138.13",
   "frequenz-client-dispatch[cli]",
 ]
 dev = [
diff --git a/src/frequenz/client/dispatch/_client.py b/src/frequenz/client/dispatch/_client.py
index 04e59f96..e05f9fc0 100644
--- a/src/frequenz/client/dispatch/_client.py
+++ b/src/frequenz/client/dispatch/_client.py
@@ -270,12 +270,9 @@ def _get_stream(
             request = StreamMicrogridDispatchesRequest(microgrid_id=int(microgrid_id))
             broadcaster = GrpcStreamBroadcaster(
                 stream_name="StreamMicrogridDispatches",
-                stream_method=lambda: cast(
-                    AsyncIterator[StreamMicrogridDispatchesResponse],
-                    self.stub.StreamMicrogridDispatches(
-                        request,
-                        timeout=self._stream_timeout_seconds,
-                    ),
+                stream_method=lambda: self.stub.StreamMicrogridDispatches(
+                    request,
+                    timeout=self._stream_timeout_seconds,
                 ),
                 transform=DispatchEvent.from_protobuf,
                 retry_strategy=LinearBackoff(interval=1, limit=None),
diff --git a/src/frequenz/client/dispatch/test/_service.py b/src/frequenz/client/dispatch/test/_service.py
index 83a0a519..a7390725 100644
--- a/src/frequenz/client/dispatch/test/_service.py
+++ b/src/frequenz/client/dispatch/test/_service.py
@@ -8,7 +8,7 @@
 import logging
 from dataclasses import dataclass, replace
 from datetime import datetime, timezone
-from typing import AsyncIterator
+from typing import AsyncIterator, TypeVar
 
 import grpc
 import grpc.aio
@@ -44,6 +44,33 @@
 _logger = logging.getLogger(__name__)
 
 
+T = TypeVar("T")
+
+
+class _MockStream(AsyncIterator[T]):
+    """A mock stream that wraps an async iterator and adds initial_metadata."""
+
+    def __init__(self, stream: AsyncIterator[T]) -> None:
+        """Initialize the mock stream.
+
+        Args:
+            stream: The stream to wrap.
+        """
+        self._iterator = stream.__aiter__()
+
+    async def initial_metadata(self) -> None:
+        """Do nothing, just to mock the grpc call."""
+        _logger.debug("Called initial_metadata()")
+
+    def __aiter__(self) -> AsyncIterator[T]:
+        """Return the async iterator."""
+        return self
+
+    async def __anext__(self) -> T:
+        """Return the next item from the stream."""
+        return await self._iterator.__anext__()
+
+
 class FakeService:
     """Dispatch mock service for testing."""
 
@@ -109,11 +136,11 @@ async def ListMicrogridDispatches(
             ),
         )
 
-    async def StreamMicrogridDispatches(
+    def StreamMicrogridDispatches(
         self,
         request: StreamMicrogridDispatchesRequest,
         timeout: int = 5,  # pylint: disable=unused-argument
-    ) -> AsyncIterator[StreamMicrogridDispatchesResponse]:
+    ) -> _MockStream[StreamMicrogridDispatchesResponse]:
         """Stream microgrid dispatches changes.
 
         Args:
@@ -122,20 +149,28 @@ async def StreamMicrogridDispatches(
 
         Returns:
             An async generator for dispatch changes.
-
-        Yields:
-            An event for each dispatch change.
         """
-        receiver = self._stream_channel.new_receiver()
-
-        async for message in receiver:
-            _logger.debug("Received message: %s", message)
-            if message.microgrid_id == MicrogridId(request.microgrid_id):
-                response = StreamMicrogridDispatchesResponse(
-                    event=message.event.event.value,
-                    dispatch=message.event.dispatch.to_protobuf(),
-                )
-                yield response
+
+        async def stream() -> AsyncIterator[StreamMicrogridDispatchesResponse]:
+            """Stream microgrid dispatches changes."""
+            _logger.debug("Starting stream for microgrid %s", request.microgrid_id)
+            receiver = self._stream_channel.new_receiver()
+
+            async for message in receiver:
+                _logger.debug("Received message: %s", message)
+                if message.microgrid_id == MicrogridId(request.microgrid_id):
+                    response = StreamMicrogridDispatchesResponse(
+                        event=message.event.event.value,
+                        dispatch=message.event.dispatch.to_protobuf(),
+                    )
+                    yield response
+                else:
+                    _logger.debug(
+                        "Skipping message for microgrid %s",
+                        message.microgrid_id,
+                    )
+
+        return _MockStream(stream())
 
     # pylint: disable=too-many-branches
     @staticmethod