Added test for partial errors

Author: maneesht

packages/firebase_data_connect/firebase_data_connect/test/src/network/rest_transport_test.dart

@@ -376,5 +376,58 @@ void main() {
         throwsA(isA<DataConnectError>()),
       );
     });
+    test('invokeOperation should decode a partial error if available',
+        () async {
+      final mockResponse = http.Response(
+        '''
+        {
+            "data": {"abc": "def"},
+            "errors": [
+                {
+                    "message": "SQL query error: pq: duplicate key value violates unique constraint movie_pkey",
+                    "locations": [],
+                    "path": [
+                        "the_matrix"
+                    ],
+                    "extensions": null
+                }
+            ]
+        }''',
+        200,
+      );
+      when(
+        mockHttpClient.post(
+          any,
+          headers: anyNamed('headers'),
+          body: anyNamed('body'),
+        ),
+      ).thenAnswer((_) async => mockResponse);
+
+      final deserializer = (String data) {
+        Map<String, dynamic> decoded = jsonDecode(data) as Map<String, dynamic>;
+        return AbcHolder(decoded['abc']!);
+      };
+
+      expect(
+        () => transport.invokeOperation(
+          'testQuery',
+          'executeQuery',
+          deserializer,
+          null,
+          null,
+          null,
+        ),
+        throwsA(predicate((e) =>
+            e is DataConnectError &&
+            e.data!['abc'] == 'def' &&
+            e.decodedData is AbcHolder &&
+            (e.decodedData as AbcHolder).abc == 'def')),
+      );
+    });
   });
 }
+
+class AbcHolder {
+  String abc;
+  AbcHolder(this.abc);
+}