public void ListMessage()
        {
            List <string> messages = new List <string> {
                "Привет", "Запрос", "Пока"
            };

            StringBuilder expect = new StringBuilder();

            foreach (string s in messages)
            {
                expect.AppendLine(s);
            }

            Notify += (string strok) => ProcessingMessage.AddMessage(strok);
            foreach (string s in messages)
            {
                Notify?.Invoke(s);
            }
            StringBuilder actual = ProcessingMessage.StringList();

            Assert.AreEqual(expect.ToString(), actual.ToString());
        }