def startTest(self, test):
        """
        Called when C{test} starts. Writes the tests name to the stream using
        a tree format.
        """
        self._testPrelude(test.id())
        self._write('%s%s ... ' % (self.indent * (len(self._lastTest)),
                                   self.getDescription(test)))
        super(TreeReporter, self).startTest(test)

        Called when C{test} starts. Writes the tests name to the stream using
        a tree format.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/trial/reporter.py