Handle & Imitate start_time rounding behavior of server

Round start_time seconds to have the same behavior as the gRPC server
frequenz-io/frequenz-service-dispatch#77

Signed-off-by: Mathias L. Baumann <[email protected]>

Author: Marenz

src/frequenz/client/dispatch/_internal_types.py

@@ -81,7 +81,7 @@ def from_protobuf(
         return DispatchCreateRequest(
             microgrid_id=pb_object.microgrid_id,
             type=pb_object.type,
-            start_time=to_datetime(pb_object.start_time),
+            start_time=rounded_start_time(to_datetime(pb_object.start_time)),
             duration=timedelta(seconds=pb_object.duration),
             selector=component_selector_from_protobuf(pb_object.selector),
             active=pb_object.is_active,
@@ -109,3 +109,20 @@ def to_protobuf(self) -> PBDispatchCreateRequest:
         pb_request.recurrence.CopyFrom(self.recurrence.to_protobuf())
 
         return pb_request
+
+
+def rounded_start_time(start_time: datetime) -> datetime:
+    """Round the start time to the nearest second.
+
+    Args:
+        start_time: The start time to round.
+
+    Returns:
+        The rounded start time.
+    """
+    # Round start_time seconds to have the same behavior as the gRPC server
+    # https://github.com/frequenz-io/frequenz-service-dispatch/issues/77
+    new_seconds = start_time.second + start_time.microsecond / 1_000_000
+    start_time = start_time.replace(microsecond=0, second=0)
+    start_time += timedelta(seconds=round(new_seconds))
+    return start_time

src/frequenz/client/dispatch/test/generator.py

@@ -8,6 +8,7 @@
 
 from frequenz.client.common.microgrid.components import ComponentCategory
 
+from .._internal_types import rounded_start_time
 from ..types import Dispatch, EndCriteria, Frequency, RecurrenceRule, Weekday
 
 
@@ -84,8 +85,10 @@ def generate_dispatch(self, microgrid_id: int | None = None) -> Dispatch:
             update_time=create_time + timedelta(seconds=self._rng.randint(0, 1000000)),
             microgrid_id=microgrid_id or self._rng.randint(0, 100),
             type=str(self._rng.randint(0, 100_000)),
-            start_time=datetime.now().astimezone(timezone.utc)
-            + timedelta(seconds=self._rng.randint(0, 1000000)),
+            start_time=rounded_start_time(
+                datetime.now(tz=timezone.utc)
+                + timedelta(seconds=self._rng.randint(0, 1000000))
+            ),
             duration=timedelta(seconds=self._rng.randint(0, 1000000)),
             selector=self._rng.choice(  # type: ignore
                 [