code: def testRegression(self):
      input = readMatrix(join(testdir, "matrix.txt"))
      expectedMean = readVector(join(testdir, "mean.txt"))
      expectedCov = readMatrix(join(testdir, "cov.txt"))
      expectedInv = readMatrix(join(testdir, "invcov.txt"))
  
      (outputMean, outputCov, outputInv) = SingleGaussian()(input)
  
      self.assertAlmostEqualVector(outputMean, expectedMean, 1e-6)
      self.assertAlmostEqualMatrix(outputCov, expectedCov, 1e-6)
      self.assertAlmostEqualMatrix(outputInv, expectedInv, 1e-6)
      self.assertInverse(outputCov, outputInv)
  
file_path: essentia/test/src/unittests/stats/test_singlegaussian.py
imports: from essentia_test import *
  from numpy import dot
label_desc: Use image node_id 2 for calling the TestSingleGaussian obj's underlying member method code with example usage: obj.testRegression() without return types