A sample exception hook, that prints useful information if an AssertionError occures

assertion_hook.py

#!/usr/bin/python
# -*- coding: utf-8 -*-
import sys
import os.path
import pprint

sys._old_excepthook = sys.excepthook


def assert_hook(exc_type, exception, traceback):
    if exc_type.__name__ == 'AssertionError':
        try:

            frame = traceback.tb_frame
            local = frame.f_locals
            line = frame.f_lineno
            codefile = frame.f_code.co_filename

            print "Assertion error in file '%s' at line %d:\n"\
                 % (codefile, line)

            with open(codefile) as f:

                statement = f.readlines()[line - 1]
                print statement

                code = compile(statement.strip(), codefile, 'single')
                names_at_line = filter(lambda name: name\
                         != 'AssertionError', code.co_names)
                names_and_vars = dict((name, local[name]) for name in
                        names_at_line)

                print 'Variables at this point:'
                pprint.pprint(names_and_vars)
        except:

            sys._old_excepthook(exc_type, exception, traceback)
    else:

        sys._old_excepthook(exc_type, exception, traceback)


sys.excepthook = assert_hook

if __name__ == '__main__':
    i = 5
    for j in range(10):
        assert j < i
        print j