code: def test_cov_execution(setup):
      data = np.array([[0, 2], [1, 1], [2, 0]]).T
      x = tensor(data, chunk_size=1)
  
      t = cov(x)
  
      res = t.execute().fetch()
      expected = np.cov(data)
      np.testing.assert_equal(res, expected)
  
      data_x = [-2.1, -1, 4.3]
      data_y = [3, 1.1, 0.12]
      x = tensor(data_x, chunk_size=1)
      y = tensor(data_y, chunk_size=1)
  
      X = stack((x, y), axis=0)
      t = cov(x, y)
      r = tall(t == cov(X))
      assert r.execute().fetch()
  
imports: import numpy
  import scipy.sparse
  import pytest
  from ....utils import ignore_warning
  from ...datasource import arange, tensor, empty
  from ...base import sort
  from ...merge import stack
  from ...reduction import all
  from ..None import average, bincount, cov, corrcoef, ptp, digitize, histogram_bin_edges, histogram, quantile, percentile, median
  from ..quantile import INTERPOLATION_TYPES
label_desc: Use image node_id 2 for calling a global function with example usage: test_cov_execution(setup) without return types