docstr: Ensure grouped parameters have identical values.
code: def test_latin_group_constant(self):
      """Ensure grouped parameters have identical values."""
      problem = {
          "num_vars": 6,
          "names": ["P1", "P2", "P3", "P4", "P5", "P6"],
          "bounds": [[-100.0, 100.0] * 6],
          "groups": ["A", "B"] * 3,
      }
      samples = sample(problem, 10, seed=42)
  
      # Group samples should have the same values
      # Get (max - min) with the `ptp()` method, the result of which should be
      # an array of zeros
      diff = samples[:, ::2].ptp(axis=1)
      assert np.all(
          diff == 0
      ), "Grouped samples do not have the same values"
  
      diff = samples[:, 1::2].ptp(axis=1)
      assert np.all(
          diff == 0
      ), "Grouped samples do not have the same values"
  
file_path: SALib/tests/sample/test_latin.py
imports: from SALib.sample.latin import sample
  from pytest import approx
  import numpy
label_desc: Use image node_id 6 for calling the TestLatinSample obj's underlying member method code with example usage: obj.test_latin_group_constant() without return types