'Called when a test fails. If C{realtime} is set, then it prints the
error to the stream.
@param test: L{ITestCase} that failed.
@param fail: L{failure.Failure} containing the error.'

def addFailure(self, test, fail):

    super(Reporter, self).addFailure(test, fail)
    if self.realtime:
        fail = self.failures[(-1)][1]
        self._write(self._formatFailureTraceback(fail))
