code: def testTriangle(self):
      size = 100
      envelope = zeros(size)
  
      for i in range(int(size / 2)):
          envelope[i] = i
      for i in range(int(size / 2), size):
          envelope[i] = size - i
      TCToTotal()(envelope)
      self.assertAlmostEqual(
          TCToTotal()(envelope), 0.5 * size / float(size - 1)
      )
  
file_path: essentia/test/src/unittests/sfx/test_tctototal.py
imports: from essentia_test import *
  from math import exp
label_desc: Use image node_id 5 for calling the TestTCToTotal obj's underlying member method code with example usage: obj.testTriangle() without return types