public void convert_back_returns_unset_value_if_value_is_not_a_date_time()
{
var converter = new DateTimeConverter();
Assert.Same(DependencyProperty.UnsetValue, converter.ConvertBack(null, null, null, null));
Assert.Same(DependencyProperty.UnsetValue, converter.ConvertBack("abc", null, null, null));
Assert.Same(DependencyProperty.UnsetValue, converter.ConvertBack(123, null, null, null));
}