TestFailure isn't a useful message

[bradleyayers]

(.env)brad-mbp:foo brad$ ./manage.py test api
Creating test database for alias 'default'...

.F

======================================================================
FAIL: unittest.case.FunctionTestCase (bars__should_list_on_get)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/brad/work/foo/.env/lib/python2.7/site-packages/attest/collectors.py", line 97, in wrapper
    func(*args[:argc])
  File "/Users/brad/work/foo/foo/apps/api/v1/tests.py", line 393, in bars__should_list_on_get
    assert json.loads(response.content) == [
  File "/Users/brad/work/foo/.env/lib/python2.7/site-packages/attest/hook.py", line 135, in assert_hook
    raise TestFailure(value, msg)
TestFailure

----------------------------------------------------------------------
Ran 22 tests in 8.501s

FAILED (failures=3)
Destroying test database for alias 'default'...