public void ValidateParameters()
        {
            Operator_nameof ono = new Operator_nameof();

              // Operator_nameof class throws ArgumentNullException using nameof on the parameter of the method.
              try { ono.ValidateParameters(null); }
              catch (ArgumentNullException ex) { Assert.AreEqual("src", ex.ParamName); }
        }
        public void NotifyPropertyChanged()
        {
            Operator_nameof ono = new Operator_nameof();

              ono.Description = "Test Description 1";
              Assert.AreEqual(0, ono.PropertyChangedInvokeCount);

              ono.PropertyChanged += Ono_PropertyChanged;
              ono.Description = "Test Description 2";
              Assert.AreEqual(1, ono.PropertyChangedInvokeCount);

              ono.PropertyChanged -= Ono_PropertyChanged;
              ono.Description = "Test Description 3";
              Assert.AreEqual(1, ono.PropertyChangedInvokeCount);
        }