code: def test_lookat():
      eye = [1, 2, 3]
      target = [-2, 1, 0]
      up = [0, 1, 0]
      M = meshutil.lookat(eye, target, up)
      assert all(M[-1] == [0, 0, 0, 1])
      eps = 1e-6
      assert np.abs(meshutil.homotrans(M, eye)).max() < eps
  
      dist = meshutil.anorm(np.float32(eye) - target)
      assert (
          np.abs(meshutil.homotrans(M, target) - [0, 0, -dist]).max()
          < eps
      )
  
imports: import pytest
  import io
  import numpy
  from lucid.misc.gl import meshutil
label_desc: Use image node_id 2 for calling a global function with example usage: test_lookat() without return types