def test_printTracebackIncludesValue(self):
        """
        When L{CopiedFailure.printTraceback} is used to print a copied failure
        which was unjellied from a L{CopyableFailure} with C{unsafeTracebacks}
        set to C{False}, the string representation of the exception value is
        included in the output.
        """
        original = pb.CopyableFailure(Exception("some reason"))
        copied = jelly.unjelly(jelly.jelly(original, invoker=DummyInvoker()))
        output = NativeStringIO()
        copied.printTraceback(output)
        exception = qual(Exception)
        expectedOutput = ("Traceback from remote host -- "
                         "{}: some reason\n".format(exception))
        self.assertEqual(expectedOutput, output.getvalue())

        When L{CopiedFailure.printTraceback} is used to print a copied failure
        which was unjellied from a L{CopyableFailure} with C{unsafeTracebacks}
        set to C{False}, the string representation of the exception value is
        included in the output.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/spread/test/test_pbfailure.py