code: def testZero(self):
      SC = SpectralContrast(sampleRate=44100)
      sc, valleys = SC(zeros(1025))
      self.assertAlmostEqual(numpy.mean(sc), -1)
      self.assertAlmostEqual(numpy.mean(valleys), numpy.log(1e-30))
  
file_path: essentia/test/src/unittests/spectral/test_spectralcontrast.py
imports: from essentia_test import *
label_desc: Use image node_id 2 for calling the TestSpectralContrast obj's underlying member method code with example usage: obj.testZero() without return types