code: def test_face_normals_indexed_faces():
      dtype_float = np.float32
      dtype_int = np.int64
      vertices = np.array(
          [[0, 0, 0], [1, 0, 0], [0, 1, 0], [0, 0, 1]],
          dtype=dtype_float,
      )
      faces = np.array(
          [[0, 2, 1], [0, 3, 2], [0, 1, 3]], dtype=dtype_int
      )
      mesh = MeshData(vertices=vertices, faces=faces)
      expected_face_normals = np.array(
          [
              [[0, 0, -1], [0, 0, -1], [0, 0, -1]],
              [[-1, 0, 0], [-1, 0, 0], [-1, 0, 0]],
              [[0, -1, 0], [0, -1, 0], [0, -1, 0]],
          ],
          dtype=dtype_float,
      )
  
      computed_face_normals = mesh.get_face_normals(indexed="faces")
  
      assert_array_equal(expected_face_normals, computed_face_normals)
  
file_path: vispy/vispy/geometry/tests/test_meshdata.py
imports: import numpy
  from numpy.testing import assert_array_equal
  from vispy.testing import run_tests_if_main
  from vispy.geometry.meshdata import MeshData
label_desc: Use image node_id 5 for calling a global function with example usage: test_face_normals_indexed_faces() without return types