code: def test_mu1tri():
      assert intvol.mu1_tri(0, 0, 0, 1, 0, 1) == 1 + np.sqrt(2) / 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 12 for calling a global function with example usage: test_mu1tri() without return types