public void ConvertShouldMakeNotNullVisible(object value)
        {
            ////Arrange
            var converter = new NotNullToVisibleConverter();

            ////Act
            var visibility = converter.Convert(value, null, null, CultureInfo.InvariantCulture);

            ////Assert
            visibility.ShouldBe(Visibility.Visible);
        }
        public void ConvertShouldMakeNullHidden()
        {
            ////Arrange
            var converter = new NotNullToVisibleConverter();

            ////Act
            var visibility = converter.Convert(null, null, null, CultureInfo.InvariantCulture);

            ////Assert
            visibility.ShouldBe(Visibility.Hidden);
        }