Ticket #117

raise a string exception in a test, nose will:

Traceback (most recent call last):
  File "/usr/local/lib/python2.4/site-packages/nose-0.10.0a1-py2.4.egg/nose/case.py", line 143, in run
    self.runTest(result)
  File "/usr/local/lib/python2.4/site-packages/nose-0.10.0a1-py2.4.egg/nose/case.py", line 161, in runTest
    test(result)
  File "/usr/local/lib/python2.4/unittest.py", line 281, in __call__
    return self.run(*args, **kwds)
  File "/usr/local/lib/python2.4/unittest.py", line 267, in run
    result.addError(self, self.__exc_info())
  File "/usr/local/lib/python2.4/site-packages/nose-0.10.0a1-py2.4.egg/nose/proxy.py", line 108, in addError
    plugins.addError(self.test, err)
  File "/usr/local/lib/python2.4/site-packages/nose-0.10.0a1-py2.4.egg/nose/plugins/manager.py", line 36, in __call__
    return self.call(*arg, **kw)
  File "/usr/local/lib/python2.4/site-packages/nose-0.10.0a1-py2.4.egg/nose/plugins/manager.py", line 89, in simple
    result = meth(*arg, **kw)
  File "/usr/local/lib/python2.4/site-packages/nose-0.10.0a1-py2.4.egg/nose/plugins/errorclass.py", line 132, in addError
    if filter(lambda c: issubclass(err_cls, c), classes):
  File "/usr/local/lib/python2.4/site-packages/nose-0.10.0a1-py2.4.egg/nose/plugins/errorclass.py", line 132, in <lambda>
    if filter(lambda c: issubclass(err_cls, c), classes):
TypeError: issubclass() arg 1 must be a class