trial exits with unhandled exception when using default reporter and a test has overridden `id` somehow

[exarkun]

from twisted.trial.unittest import TestCase

class Broken(TestCase):
    def setUp(self):
        self.id = None


    def test_foo(self):
        1 / 0

This failure brought to you by inheritance and the number 7.

[jml]

What's the expected behaviour?

[exarkun]

Handle the exception, report the problem in a user-friendly way. Make it easy and obvious to the person running trial how the test code is flawed.