code: def test_degree_warning(self, xp, scp, kernel):
      y = xp.linspace(0, 1, 5)[:, None]
      d = xp.zeros(5)
      deg = _NAME_TO_MIN_DEGREE[kernel]
      with warnings.catch_warnings():
          warnings.simplefilter("error")
          self.build(
              scp, y, d, epsilon=1.0, kernel=kernel, degree=deg - 1
          )
  
imports: import pickle
  import pytest
  import warnings
  import numpy
  from numpy.linalg import LinAlgError
  import cupy
  import cupyx
  from cupy import testing
  import cupyx.scipy.interpolate
  from cupyx.scipy.interpolate._rbfinterp import _AVAILABLE, _SCALE_INVARIANT, _NAME_TO_MIN_DEGREE, NAME_TO_FUNC, _monomial_powers, polynomial_matrix, kernel_matrix
label_desc: Use image node_id 19 for calling the _TestRBFInterpolator obj's underlying member method code with example usage: obj.test_degree_warning(xp, scp, kernel) without return types