Add test for snapshot

test_tjnetwork.py

@@ -1153,6 +1153,51 @@ class TestApi:
         self.leave(p)
 
 
+    def test_snapshot(self):
+        p = "test_snapshot"
+        self.enter(p)
+
+        add_junction(p, ChangeSet({'id': 'j1', 'x': 0.0, 'y': 10.0, 'elevation': 20.0}))
+        add_junction(p, ChangeSet({'id': 'j2', 'x': 0.0, 'y': 10.0, 'elevation': 20.0}))
+        add_junction(p, ChangeSet({'id': 'j3', 'x': 0.0, 'y': 10.0, 'elevation': 20.0}))
+        add_junction(p, ChangeSet({'id': 'j4', 'x': 0.0, 'y': 10.0, 'elevation': 20.0}))
+
+        client_op = get_current_operation(p)
+        assert client_op == 4
+        assert take_snapshot(p, 'x') == 4
+
+        execute_undo(p)
+        execute_undo(p)
+        add_junction(p, ChangeSet({'id': 'j5', 'x': 0.0, 'y': 10.0, 'elevation': 20.0}))
+        add_junction(p, ChangeSet({'id': 'j6', 'x': 0.0, 'y': 10.0, 'elevation': 20.0}))
+
+        assert take_snapshot(p, 'xx') == 6
+
+        cs = sync_with_server(p, client_op).operations
+        cs[0]['operation'] = API_DELETE
+        cs[0]['id'] = 'j4'
+        cs[1]['operation'] = API_DELETE
+        cs[1]['id'] = 'j3'
+        cs[2]['operation'] = API_ADD
+        cs[2]['id'] = 'j5'
+        cs[3]['operation'] = API_ADD
+        cs[3]['id'] = 'j6'
+
+        cs = pick_snapshot(p, 'x').operations
+        cs[0]['operation'] = 'delete'
+        cs[0]['id'] = 'j6'
+        cs[1]['operation'] = 'delete'
+        cs[1]['id'] = 'j5'
+        cs[2]['operation'] = 'add'
+        cs[2]['id'] = 'j3'
+        cs[3]['operation'] = 'add'
+        cs[3]['id'] = 'j4'
+
+        assert get_nodes(p) == ['j1', 'j2', 'j3', 'j4']
+
+        self.leave(p)
+
+
     def test_batch_commands(self):
         p = 'test_valve_op'
         self.enter(p)