code: def test_cov2corr():
      from brainiak.utils.utils import cov2corr
      import numpy as np
  
      cov = np.array([[4, 3, 0], [3, 9, 0], [0, 0, 1]])
      corr = cov2corr(cov)
      assert np.allclose(
          corr, np.array([[1, 0.5, 0], [0.5, 1, 0], [0, 0, 1]])
      ), "Converting from covariance matrix to correlation incorrect"
  
file_path: brainiak/tests/utils/test_utils.py
imports: import pytest
label_desc: Use image node_id 4 for calling a global function with example usage: test_cov2corr() without return types