code: def testEmpty(self):
      # Empty input should raise an exception
      self.assertComputeFails(Onsets(), array([[]]), [])
  
file_path: essentia/test/src/unittests/rhythm/test_onsets.py
imports: from essentia_test import *
label_desc: Use image node_id 5 for calling the TestOnsets obj's underlying member method code with example usage: obj.testEmpty() without return types