id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
29024	`TestContextDecorator` never exits if `setUp` fails in tests	Anthony King	Kamil	"when using `TestContextDecorator` as a class decorator, `enable` is called just before `Test.setUp`, and `disable` is called after `Test.tearDown`.

unfortunately, `tearDown` is not called in the event of a failure inside `setUp`. This can result in unexpected behaviour.

Even though this class is not documented, there are decorators that use it that are.


example:


{{{#!python
class example_decorator(TestContextDecorator):
    some_var = False

    def enable(self):
        self.__class__.some_var = True

    def disable(self):
        self.__class__.some_var = False

class Example1TestCase(TestCase):
    def test_var_is_false(self):
        # some_var will be False
        self.assertFalse(example_decorator.some_var)


@example_decorator()
class Example2TestCase(TestCase):
    def setUp(self):
        raise Exception

    def test_var_is_true(self):
        # won't be hit due to exception in setUp
        self.assertTrue(example_decorator.some_var)


class Example3TestCase(TestCase):
    def test_var_is_false(self):
        # some_var will be True now due to no cleanup in Example2TestCase
        self.assertFalse(example_decorator.some_var)

}}}
output:
{{{
.EF
======================================================================
ERROR: test_var_is_true (example.tests.Example2TestCase)
----------------------------------------------------------------------
... Traceback

======================================================================
FAIL: test_var_is_false (example.tests.Example3TestCase)
----------------------------------------------------------------------
...
AssertionError: True is not false

Ran 3 tests in 0.007s

FAILED (failures=1, errors=1)
}}}

There are 2 potential fixes here:
- decorate `setUpClass` and `tearDownClass`
- use `addCleanup` inside the `setUp` decorator

`addCleanup` will always run, and will only ever be registered if the context manager was successfully enabled.

It would also be useful to have this class documented, however that's out of scope of this ticket."	Bug	closed	Testing framework	dev	Normal	fixed			Accepted	1	0	1	1	1	0