code: def test_reg_aladin():
      """tests for reg_aladin interface"""
      # Create a reg_aladin object
      nr_aladin = RegAladin()
  
      # Check if the command is properly defined
      assert nr_aladin.cmd == get_custom_path("reg_aladin")
  
      # test raising error with mandatory args absent
      with pytest.raises(ValueError):
          nr_aladin.run()
  
      # Assign some input data
      ref_file = example_data("im1.nii")
      flo_file = example_data("im2.nii")
      rmask_file = example_data("mask.nii")
      nr_aladin.inputs.ref_file = ref_file
      nr_aladin.inputs.flo_file = flo_file
      nr_aladin.inputs.rmask_file = rmask_file
      nr_aladin.inputs.omp_core_val = 4
  
      cmd_tmp = "{cmd} -aff {aff} -flo {flo} -omp 4 -ref {ref} -res {res} \
  -rmask {rmask}"
  
      expected_cmd = cmd_tmp.format(
          cmd=get_custom_path("reg_aladin"),
          aff="im2_aff.txt",
          flo=flo_file,
          ref=ref_file,
          res="im2_res.nii.gz",
          rmask=rmask_file,
      )
  
      assert nr_aladin.cmdline == expected_cmd
  
imports: import pytest
  from ....testing import example_data
  from ..None import get_custom_path, RegAladin, RegF3D
  from .test_regutils import no_nifty_tool
label_desc: Use image node_id 1 for calling a global function with example usage: test_reg_aladin() without return types