code: def testZero(self):
      inputSize = 512
      signalZero = [0] * inputSize
      expectedZero = [0] * int(inputSize / 2 + 1)
      outputZero = Spectrum()(signalZero)
      self.assertEqualVector(outputZero, expectedZero)
  
file_path: essentia/test/src/unittests/standard/test_spectrum.py
imports: from essentia_test import *
label_desc: Use image node_id 4 for calling the TestSpectrum obj's underlying member method code with example usage: obj.testZero() without return types