Merge pull request #32 from Marenz/freeze-dispatch

Make `Dispatch` class frozen

Author: Marenz

RELEASE_NOTES.md

@@ -6,7 +6,7 @@
 
 ## Upgrading
 
-<!-- Here goes notes on how to upgrade from previous versions, including deprecations and what they should be replaced with -->
+- The `Dispatch` class is now a frozen dataclass, meaning that it is immutable. Modifications can still be done using `replace`: `dispatch = replace(dispatch, start_time=new_start_time)`.
 
 ## New Features
 

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

@@ -6,7 +6,7 @@
 Useful for testing.
 """
 import dataclasses
-from dataclasses import dataclass
+from dataclasses import dataclass, replace
 from datetime import datetime, timezone
 
 import grpc
@@ -175,7 +175,10 @@ async def UpdateMicrogridDispatch(
                             )[:]
 
         dispatch = Dispatch.from_protobuf(pb_dispatch)
-        dispatch.update_time = datetime.now(tz=timezone.utc)
+        dispatch = replace(
+            dispatch,
+            update_time=datetime.now(tz=timezone.utc),
+        )
 
         self.dispatches[index] = dispatch
 

src/frequenz/client/dispatch/types.py

@@ -244,7 +244,7 @@ class TimeIntervalFilter:
     """Filter by end_time < end_to."""
 
 
-@dataclass(kw_only=True)
+@dataclass(kw_only=True, frozen=True)
 class Dispatch:
     """Represents a dispatch operation within a microgrid system."""
 

tests/test_dispatch_client.py

@@ -3,11 +3,35 @@
 
 """Tests for the frequenz.client.dispatch package."""
 
+from dataclasses import replace
+
 import grpc
 from pytest import raises
 
 from frequenz.client.dispatch.test.client import FakeClient, to_create_params
 from frequenz.client.dispatch.test.generator import DispatchGenerator
+from frequenz.client.dispatch.types import Dispatch
+
+
+def _update(dispatch: Dispatch, created: Dispatch) -> Dispatch:
+    """Update the dispatch.
+
+    Updates the id, create_time and update_time of the local dispatch
+    with the values from the created dispatch.
+
+    Args:
+        dispatch: The local dispatch.
+        created: The created dispatch.
+
+    Returns:
+        The updated dispatch.
+    """
+    return replace(
+        dispatch,
+        id=created.id,
+        create_time=created.create_time,
+        update_time=created.update_time,
+    )
 
 
 async def test_create_dispatch() -> None:
@@ -22,8 +46,7 @@ async def test_create_dispatch() -> None:
 
     # Before we can compare, we need to set the create_time and update_time
     # as they are generated by the (fake) remote point
-    sample.create_time = stored_dispatches[0].create_time
-    sample.update_time = stored_dispatches[0].update_time
+    sample = _update(sample, stored_dispatches[0])
 
     assert len(stored_dispatches) == 1
     assert stored_dispatches[0] == sample
@@ -58,9 +81,7 @@ async def test_list_create_dispatches() -> None:
         if dispatch is None:
             raise AssertionError("Dispatch not found")
 
-        sample.id = dispatch.id
-        sample.create_time = dispatch.create_time
-        sample.update_time = dispatch.update_time
+        sample = _update(sample, dispatch)
         assert dispatch == sample
 
 
@@ -75,9 +96,7 @@ async def test_update_dispatch() -> None:
     dispatch = await anext(client.list(microgrid_id=sample.microgrid_id), None)
     assert dispatch is not None
 
-    sample.id = dispatch.id
-    sample.create_time = dispatch.create_time
-    sample.update_time = dispatch.update_time
+    sample = _update(sample, dispatch)
     assert dispatch == sample
 
     await client.update(dispatch.id, {"recurrence.interval": 4})
@@ -95,9 +114,7 @@ async def test_get_dispatch() -> None:
     dispatch = await anext(client.list(microgrid_id=sample.microgrid_id), None)
     assert dispatch is not None
 
-    sample.id = dispatch.id
-    sample.create_time = dispatch.create_time
-    sample.update_time = dispatch.update_time
+    sample = _update(sample, dispatch)
     assert dispatch == sample
 
     assert await client.get(dispatch.id) == dispatch
@@ -122,9 +139,7 @@ async def test_delete_dispatch() -> None:
     dispatch = await anext(client.list(microgrid_id=sample.microgrid_id), None)
     assert dispatch is not None
 
-    sample.id = dispatch.id
-    sample.create_time = dispatch.create_time
-    sample.update_time = dispatch.update_time
+    sample = _update(sample, dispatch)
     assert dispatch == sample
 
     await client.delete(dispatch.id)