Python Unit Testing: Automatically Running the Debugger when a test fails

Question

Is there a way to automatically start the debugger at the point at which a unittest fails?

Right now I am just using pdb.set_trace() manually, but this is very tedio

Answer 1

import unittest
import sys
import pdb
import functools
import traceback
def debug_on(*exceptions):
    if not exceptions:
        exceptions = (AssertionError, )
    def decorator(f):
        @functools.wraps(f)
        def wrapper(*args, **kwargs):
            try:
                return f(*args, **kwargs)
            except exceptions:
                info = sys.exc_info()
                traceback.print_exception(*info) 
                pdb.post_mortem(info[2])
        return wrapper
    return decorator

class tests(unittest.TestCase):
    @debug_on()
    def test_trigger_pdb(self):
        assert 1 == 0

I corrected the code to call post_mortem on the exception instead of set_trace.