Comment 3 for bug 1188420

4:
FAIL: f.TestCase.test_without_trace
----------------------------------------------------------------------
Traceback (most recent call last):
  File "f.py", line 19, in test_without_trace
    self.useFixture(WrongFixtureWithoutTrace())
  File "testtools/testcase.py", line 591, in useFixture
    fixture.setUp()
  File "f.py", line 8, in setUp
    raise AssertionError('error')
AssertionError: error

Note that this too stops at the testcase methods, which filtering is happening before the content object : we appear to have two traceback manipulating locations/routines, so we need to fix that too.

Of particular interest note that we're filtering the trace in precisely the wrong direction. low count - show top, not the bottom.