code: def test_mu2tri():
      assert intvol.mu2_tri(0, 0, 0, 1, 0, 1) == 1.0 / 2
  
imports: from itertools import combinations
  import numpy
  import numpy.linalg
  import pytest
  from numpy.testing import assert_almost_equal, assert_array_equal
  from ..None import intvol
label_desc: Use image node_id 11 for calling a global function with example usage: test_mu2tri() without return types