code: def test_twosample_non_null(self):
      data1, vardata1, XYZ = make_data(n=20)
      data2, vardata2 = data1 - 10, vardata1
      # rfx calibration
      P = pt.permutation_test_twosample(
          data1, data2, XYZ, ndraws=ndraws
      )
      # mfx calibration
      P = pt.permutation_test_twosample(
          data1,
          data2,
          XYZ,
          vardata1=vardata1,
          vardata2=vardata2,
          stat_id="student_mfx",
          ndraws=ndraws,
      )
      p_values, cluster_results, region_results = P.calibrate(
          nperms=nperms
      )
      cpval = p_values["Corr_p_values"]
      assert_array_equal(cpval, np.zeros_like(cpval))
  
file_path: nipy/nipy/labs/group/tests/test_permutation_test.py
imports: import unittest
  import numpy
  from numpy.testing import assert_array_equal
  from nipy.algorithms.graph import wgraph_from_3d_grid
  from ..None import permutation_test
label_desc: Use image node_id 5 for calling the test_permutation_test obj's underlying member method code with example usage: obj.test_twosample_non_null() without return types