public void Bind_should_map_a_failed_exceptional_to_another_FAILED_exceptional()
{
Exceptional <int> exceptional = new InvalidOperationException("invalid");
var mapped = exceptional.Bind(i => Success(i.ToString()));
mapped.IsException.Should().BeTrue();
mapped.OnException(ex =>
{
ex.Should().BeOfType <InvalidOperationException>();
ex.Message.Should().Be("invalid");
});
}