testscenarios/fixtures issue

bash

virtualenv testscenarios-bug
source testscenarios-bug/bin/activate
pip install testtools testscenarios fixtures
cat <<EOF > test_bug.py
import os

import fixtures
import testscenarios
import testtools


class TestBug(testscenarios.TestWithScenarios,
              testtools.TestCase):

    scenarios = [
        ('s1', dict(v1=1, v2=1)),
        ('s2', dict(v1=1, v2=2))
    ]

    def setUp(self):

        super(TestBug, self).setUp()
        self.tempdir = self.useFixture(fixtures.TempDir())
        self.path = self.tempdir.path
        self.addOnException(self.checktmpdir)

    def checktmpdir(self, exc_info):
        if not os.path.exists(self.path):
            # this occurs for the failing test, which makes it very
            # difficult to get info from a TempDir fixture *only* when the
            # test fails. Almost as though the cleanup is called before
            # the addOnException get's called.
            print("%s: Bug hit! Directory '%s' should still exist" %
                  (self.__class__.__name__, self.path))
        else:
            print("%s: Directory '%s' still exists" %
                  (self.__class__.__name__, self.path))

    def test_run(self):
        self.assertEquals(self.v1, self.v2)


class TestBugWorking(testtools.TestCase):

    def setUp(self):

        super(TestBugWorking, self).setUp()
        self.tempdir = self.useFixture(fixtures.TempDir())
        self.path = self.tempdir.path
        self.addOnException(self.checktmpdir)

    def checktmpdir(self, exc_info):
        if not os.path.exists(self.path):
            print("%s: Bug hit! Directory '%s' should still exist" %
                  (self.__class__.__name__, self.path))
        else:
            # we only hit this for the failing test in a non-scenarios
            # approach, which is as excepted here
            print("%s: Directory '%s' still exists" %
                  (self.__class__.__name__, self.path))

    def test_run_s1(self):
        self.assertEquals(1, 1)

    def test_run_s2(self):
        self.assertEquals(1, 2)
EOF

python -m testtools.run discover -t .

output

Tests running...
TestBug: Bug hit! Directory '/tmp/tmpsDRKx3' should still exist
TestBug: Directory '/tmp/tmppBQSBt' still exists
TestBugWorking: Directory '/tmp/tmpL6yopi' still exists
======================================================================
FAIL: test_bug.TestBug.test_run(s2)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/dara/tmp/testbug/test_bug.py", line 36, in test_run
    self.assertEquals(self.v1, self.v2)
  File "/home/dara/tmp/testbug/testscenarios-bug/lib/python2.7/site-packages/testtools/testcase.py", line 350, in assertEqual
    self.assertThat(observed, matcher, message)
  File "/home/dara/tmp/testbug/testscenarios-bug/lib/python2.7/site-packages/testtools/testcase.py", line 435, in assertThat
    raise mismatch_error
testtools.matchers._impl.MismatchError: 1 != 2
======================================================================
FAIL: test_bug.TestBugWorking.test_run_s2
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/dara/tmp/testbug/test_bug.py", line 62, in test_run_s2
    self.assertEquals(1, 2)
  File "/home/dara/tmp/testbug/testscenarios-bug/lib/python2.7/site-packages/testtools/testcase.py", line 350, in assertEqual
    self.assertThat(observed, matcher, message)
  File "/home/dara/tmp/testbug/testscenarios-bug/lib/python2.7/site-packages/testtools/testcase.py", line 435, in assertThat
    raise mismatch_error
testtools.matchers._impl.MismatchError: 1 != 2

Ran 4 tests in 0.003s
FAILED (failures=2)