The traceback module and sys.exc_info are overkill for tracking down the source of an exception. That's all in the default traceback. So instead of calling exit(1) just re-raise:
try:
assert "birthday cake" == "ice cream cake", "Should've asked for pie"
except AssertionError:
print 'Houston, we have a problem.'
raise
Which gives the following output that includes the offending statement and line number:
Houston, we have a problem.
Traceback (most recent call last):
File "/tmp/poop.py", line 2, in <module>
assert "birthday cake" == "ice cream cake", "Should've asked for pie"
AssertionError: Should've asked for pie
Similarly the logging module makes it easy to log a traceback for any exception (including those which are caught and never re-raised):
import logging
try:
assert False == True
except AssertionError:
logging.error("Nothing is real but I can't quit...", exc_info=True)