def METHOD_NAME(self):
    mel_basis = np_transforms.build_mel_basis(**self.config)
    spec = np.random.rand(self.config.fft_size // 2 + 1, 20)  # [C, T]
    mel = np_transforms.spec_to_mel(spec=spec, mel_basis=mel_basis)
    self.assertEqual(mel.shape, (self.config.num_mels, 20))