code: def testCircle(self):
      # Tests a few points, including one at phase=pi, separately and then all together at the same time
      c2p = CartesianToPolar()
  
      circle = {
          (1, 0): (1, 0),
          (sqrt(2) / 2, sqrt(2) / 2): (1, pi / 4),
          (1, 1): (sqrt(2), pi / 4),
          (0, 1): (1, pi / 2),
          (-1, 0): (1, pi),
          (0, -1): (1, -pi / 2),
      }
  
      for c, p in circle.items():
          mag, phase = c2p(numpy.array([complex(*c)], dtype="c8"))
  
          self.assertAlmostEqualVector(mag, [p[0]])
          self.assertAlmostEqualVector(phase, [p[1]])
  
      circleCart = circle.keys()
      circlePolar = [circle[key] for key in circleCart]
  
      circleCart = numpy.array(
          [complex(*c) for c in circleCart], dtype="c8"
      )
      circleMag = [c[0] for c in circlePolar]
      circlePhase = [c[1] for c in circlePolar]
  
      cmag, cphase = c2p(circleCart)
  
      self.assertAlmostEqualVector(cmag, circleMag, 1e-6)
      self.assertAlmostEqualVector(cphase, circlePhase, 1e-6)
  
imports: from essentia_test import *
  from math import *
label_desc: Use image node_id 3 for calling the TestCartesianToPolar obj's underlying member method code with example usage: obj.testCircle() without return types