Update equalstester in DeviceMetadata. (quantumlib#4840)

Part of quantumlib#4743

Author: MichaelBroughton

cirq-core/cirq/devices/device.py

@@ -207,6 +207,7 @@ def __init__(
 
         self._nx_graph = nx_graph
 
+    @property
     def qubit_set(self) -> Optional[FrozenSet['cirq.Qid']]:
         """Returns a set of qubits on the device, if possible.
 
@@ -215,6 +216,7 @@ def qubit_set(self) -> Optional[FrozenSet['cirq.Qid']]:
         """
         return self._qubits_set
 
+    @property
     def nx_graph(self) -> Optional['nx.Graph']:
         """Returns a nx.Graph where nodes are qubits and edges are couple-able qubits.
 
@@ -226,13 +228,12 @@ def nx_graph(self) -> Optional['nx.Graph']:
     def _value_equality_values_(self):
         graph_equality = None
         if self._nx_graph is not None:
-            graph_equality = (sorted(self._nx_graph.nodes()), sorted(self._nx_graph.edges()))
-
-        qubit_equality = None
-        if self._qubits_set is not None:
-            qubit_equality = sorted(list(self._qubits_set))
+            graph_equality = (
+                tuple(sorted(self._nx_graph.nodes())),
+                tuple(sorted(self._nx_graph.edges(data='directed'))),
+            )
 
-        return qubit_equality, graph_equality
+        return self._qubits_set, graph_equality
 
     def _json_dict_(self):
         graph_payload = ''

cirq-core/cirq/devices/device_test.py

@@ -82,12 +82,12 @@ def test_metadata():
     qubits = cirq.LineQubit.range(4)
     graph = nx.star_graph(3)
     metadata = cirq.DeviceMetadata(qubits, graph)
-    assert metadata.qubit_set() == frozenset(qubits)
-    assert metadata.nx_graph() == graph
+    assert metadata.qubit_set == frozenset(qubits)
+    assert metadata.nx_graph == graph
 
     metadata = cirq.DeviceMetadata()
-    assert metadata.qubit_set() is None
-    assert metadata.nx_graph() is None
+    assert metadata.qubit_set is None
+    assert metadata.nx_graph is None
 
 
 def test_metadata_json_load_logic():
@@ -103,3 +103,19 @@ def test_metadata_json_load_logic():
     str_rep = cirq.to_json(metadata)
     output = cirq.read_json(json_text=str_rep)
     assert metadata == output
+
+
+def test_metadata_equality():
+    qubits = cirq.LineQubit.range(4)
+    graph = nx.star_graph(3)
+    graph2 = nx.star_graph(3)
+    graph.add_edge(1, 2, directed=False)
+    graph2.add_edge(1, 2, directed=True)
+
+    eq = cirq.testing.EqualsTester()
+    eq.add_equality_group(cirq.DeviceMetadata(qubits, graph))
+    eq.add_equality_group(cirq.DeviceMetadata(None, graph))
+    eq.add_equality_group(cirq.DeviceMetadata(qubits, None))
+    eq.add_equality_group(cirq.DeviceMetadata(None, None))
+
+    assert cirq.DeviceMetadata(None, graph) != cirq.DeviceMetadata(None, graph2)