code: def test_total_variance():
      a = np.array([78, 12, 0.5, 2, 97, 33])
      actual = _total_variance(a)
      expected = 0.19347
  
      assert_allclose(actual, expected, rtol=1e-4)
  
file_path: SALib/tests/test_test_functions.py
imports: from pytest import raises
  from numpy.testing import assert_allclose
  import numpy
  from SALib.test_functions.Sobol_G import evaluate, _total_variance, _partial_first_order_variance, sensitivity_index, total_sensitivity_index
  from SALib import ProblemSpec
label_desc: Use image node_id 6 for calling a global function with example usage: test_total_variance() without return types