Too much stack shown on re-raised exceptions

I just got this from an assertRaises failure:

======================================================================
ERROR: tests.test_database.TestDatabase.test_double_insert
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/jml/src/pkgme-binary/use-description/devportalbinary/tests/test_database.py", line 55, in test_double_insert
    db.insert_new_library, 'foo-src', 'libfoo.so.0', 'foo')
  File "/home/jml/src/testtools/trunk/testtools/testcase.py", line 389, in assertRaises
    self.assertThat(lambda: callableObj(*args, **kwargs), matcher)
  File "/home/jml/src/testtools/trunk/testtools/testcase.py", line 401, in assertThat
    mismatch = matcher.match(matchee)
  File "/home/jml/src/testtools/trunk/testtools/matchers.py", line 798, in match
    mismatch = self.exception_matcher.match(exc_info)
  File "/home/jml/src/testtools/trunk/testtools/matchers.py", line 546, in match
    mismatch = matcher.match(matchee)
  File "/home/jml/src/testtools/trunk/testtools/testcase.py", line 380, in match
    reraise(*matchee)
  File "/home/jml/src/testtools/trunk/testtools/matchers.py", line 791, in match
    result = matchee()
  File "/home/jml/src/testtools/trunk/testtools/testcase.py", line 389, in <lambda>
    self.assertThat(lambda: callableObj(*args, **kwargs), matcher)
  File "devportalbinary/database.py", line 338, in insert_new_library
    (unicode(source_package_name), unicode(library_name), unicode(dependency)))
  File "/usr/lib/python2.7/dist-packages/storm/store.py", line 108, in execute
    return self._connection.execute(statement, params, noresult)
  File "/usr/lib/python2.7/dist-packages/storm/database.py", line 238, in execute
    raw_cursor = self.raw_execute(statement, params)
  File "/usr/lib/python2.7/dist-packages/storm/databases/sqlite.py", line 154, in raw_execute
    return Connection.raw_execute(self, statement, params)
  File "/usr/lib/python2.7/dist-packages/storm/database.py", line 322, in raw_execute
    self._check_disconnect(raw_cursor.execute, *args)
  File "/usr/lib/python2.7/dist-packages/storm/database.py", line 371, in _check_disconnect
    return function(*args, **kwargs)
IntegrityError: columns source_package_name, library, dependency are not unique
Ran 64 tests in 10.907s (+0.235s)

Most of that stack is irrelevant to the test at hand, and is only valuable for debugging testtools itself. It should not be shown to end users by default.