class_docstr: Unit test for synthetic function. 
class_docstr_tok: ["Unit","test","for","synthetic","function","."]
docstr: A single function to do the testing. 
docstr_tok: ["A","single","function","to","do","the","testing","."]
code: def _test_for_test_err(cls, test_vals_1, test_vals_2, noise_scale):
      """A single function to do the testing."""
      test_err = np.linalg.norm(
          np.array(test_vals_1) - np.array(test_vals_2)
      ) / np.sqrt(len(test_vals_1))
      assert test_err <= _TOL + 2 * noise_scale
      return test_err
  
imports: import os
  import numpy
  from .None import cp_domain_utils, experiment_caller
  from ..utils import euclidean_synthetic_functions
  from ..utils.base_test_class import BaseTestClass, execute_tests
  from ..utils.ancillary_utils import get_list_of_floats_as_str
  from ..test_data.park2_4.park2_4 import park2_4
  from ..test_data.park2_4.park2_4_mf import park2_4_mf
  from ..test_data.park2_4.park2_4_mf import cost
  from ..test_data.park1_3.park1_3 import park1_3
  from ..test_data.park1_3.park1_3_mf import park1_3_mf
  from ..test_data.park1_3.park1_3_mf import cost
label_desc: Use image node_id 5 for calling the EuclideanFunctionCallerTestCase obj's underlying member method code with example usage: obj._test_for_test_err(cls, test_vals_1, test_vals_2, noise_scale) and returns: test_err