code: def test_saltelli_warning():
      # Ensure error is raised when n_samples not a power of 2
      cmd = f"salib sample saltelli -p {ishigami_fp} -o {test_data} -n 511".split()
      result = subprocess.check_output(cmd, stderr=subprocess.STDOUT)
      assert "Warning" in str(result)
  
      # Ensure warning is raised when skip_values < n_samples
      cmd = (
          f"salib sample saltelli -p {ishigami_fp} -o {test_data}"
          " -n 2048 --skip-values 1024"
      ).split()
      result = subprocess.check_output(cmd, stderr=subprocess.STDOUT)
      assert "Warning" in str(result)
  
      # Ensure error is raised when skip_values not a power of 2
      cmd = (
          f"salib sample saltelli -p {ishigami_fp} -o {test_data}"
          " -n 512 --skip-values 1025"
      ).split()
      result = subprocess.check_output(cmd, stderr=subprocess.STDOUT)
      assert "Warning" in str(result)
  
file_path: SALib/tests/test_cli_sample.py
imports: import os
  from os.path import join
  import subprocess
label_desc: Use image node_id 8 for calling a global function with example usage: test_saltelli_warning() without return types