code: def testZero(self):
      # Inputting zeros should return zero. Try with different sizes
      size = 1024
      while size >= 256:
          outs = NNLSChroma(frameSize=size)(
              array(zeros([2, 256])), array(zeros(3)), array(zeros(2))
          )
  
          self.assertEqual(
              outs[0].sum() + outs[1].sum() + numpy.sum(outs[-2:]), 0.0
          )
          size = int(size / 2)
  
file_path: essentia/test/src/unittests/tonal/test_nnlschroma.py
imports: from essentia_test import *
  import numpy
label_desc: Use image node_id 2 for calling the TestNNLSChroma obj's underlying member method code with example usage: obj.testZero() without return types