Just off the top of my head, would checking the limit of the function at the point of dispute do?
For instance, >>> a = limit(log(x), x, 0) gives - oo -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sympy?hl=en-US. For more options, visit https://groups.google.com/groups/opt_out.
