Fix uses of Connection as if they were tuples

The `Connection` type in the external microgrid API is a dataclass
instead of a tuple, so we need to convert it when a tuple is expected.

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

Author: llucax

src/frequenz/sdk/microgrid/component_graph.py

@@ -22,6 +22,7 @@
 """
 
 import asyncio
+import dataclasses
 import logging
 from abc import ABC, abstractmethod
 from collections.abc import Callable, Iterable
@@ -513,7 +514,7 @@ def refresh_from(
         for component in components:
             new_graph.add_node(component.component_id, **asdict(component))
 
-        new_graph.add_edges_from(connections)
+        new_graph.add_edges_from(dataclasses.astuple(c) for c in connections)
 
         # check if we can construct a valid ComponentGraph
         # from the new NetworkX graph data

tests/microgrid/test_graph.py

@@ -1431,7 +1431,7 @@ def test_graph_correction(self) -> None:
         }
         assert len(graph.components()) == len(expected)
         assert set(graph.components()) == expected
-        assert list(graph.connections()) == [(1, 2)]
+        assert list(graph.connections()) == [Connection(1, 2)]
 
         # invalid graph data that (for now at least)
         # cannot be corrected
@@ -1445,7 +1445,7 @@ def test_graph_correction(self) -> None:
         # graph is still in last known good state
         assert len(graph.components()) == len(expected)
         assert set(graph.components()) == expected
-        assert list(graph.connections()) == [(1, 2)]
+        assert list(graph.connections()) == [Connection(1, 2)]
 
         # invalid graph data where there is no grid
         # endpoint but a node has the magic value 0
@@ -1462,7 +1462,7 @@ def test_graph_correction(self) -> None:
         # graph is still in last known good state
         assert len(graph.components()) == len(expected)
         assert set(graph.components()) == expected
-        assert list(graph.connections()) == [(1, 2)]
+        assert list(graph.connections()) == [Connection(1, 2)]
 
         # with the callback, this can be corrected
         graph.refresh_from(
@@ -1477,4 +1477,4 @@ def test_graph_correction(self) -> None:
         assert len(graph.components()) == len(expected)
         assert set(graph.components()) == expected
 
-        assert list(graph.connections()) == [(0, 8)]
+        assert list(graph.connections()) == [Connection(0, 8)]