def METHOD_NAME(self):
    " The easiest test: make sure the CP is added correctly. "
    fft_len = 8
    cp_len = 2
    expected_result = [6, 7, 0, 1, 2, 3, 4, 5, 6, 7,
                       6, 7, 0, 1, 2, 3, 4, 5, 6, 7]
    src = blocks.vector_source_c(list(range(fft_len)) * 2, False, fft_len)
    cp = digital.ofdm_cyclic_prefixer(fft_len, fft_len + cp_len)
    sink = blocks.vector_sink_c()
    self.tb.connect(src, cp, sink)
    self.tb.run()
    self.assertEqual(sink.data(), expected_result)