output

   py.test -s test.py
================================= test session starts ==================================
platform darwin -- Python 2.7.9 -- py-1.4.27 -- pytest-2.6.4
collected 2 items

test.py
beginning


in passing test

.
rollback


beginning


in failing test

F
rollback



======================================= FAILURES =======================================
_________________________ TestMyWidget.test_my_failing_widget __________________________

self = <test.TestMyWidget instance at 0x10cd01cb0>
db_transaction = <test.Object object at 0x10ccfded0>

    def test_my_failing_widget(self, db_transaction):
        print "\nin failing test\n"
>       raise Exception()
E       Exception

test.py:39: Exception
========================== 1 failed, 1 passed in 0.01 seconds ==========================

test.py

class Object(object):
    pass

orm = Object()

orm.session = Object()

def begin():
    print "\nbeginning\n"

def rollback():
    print "\nrollback\n"

orm.session.begin = begin
orm.session.rollback = rollback

import pytest

@pytest.fixture()
def db_transaction(request):
    orm.session.begin()

    def fin():
        orm.session.rollback()

    request.addfinalizer(fin)

    return orm.session


class TestMyWidget:

    def test_my_widget(self, db_transaction):
        print "\nin passing test\n"

    def test_my_failing_widget(self, db_transaction):
        print "\nin failing test\n"
        raise Exception()