code: def test_dtw_global_inf():
      # What should we do if backtracking fails in full sequence mode?
      # This will happen if the inner loop of bt aborts prematurely
      # by walking off the edge of the cost array instead of
      # path-following to (0, 0)
  
      # Construct a cost matrix where full alignment is impossible
      C = np.zeros((4, 4), dtype=float)
      C[-1, -1] = np.inf
      with pytest.raises(librosa.ParameterError):
          librosa.sequence.dtw(C=C, subseq=False)
  
imports: import librosa
  import numpy
  from scipy.spatial.distance import cdist
  import pytest
  from test_core import srand
label_desc: Use image node_id 20 for calling a global function with example usage: test_dtw_global_inf() without return types