old_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  """Tests for the Hamiltonian method."""
  
  import pytest
  from numpy.testing import assert_allclose
  
  from parameters import KPT, T_VALUES
  
  
  @pytest.mark.parametrize("kpt", KPT)
  @pytest.mark.parametrize("t_values", T_VALUES)
  @pytest.mark.parametrize("convention", [1, 2])
  def test_simple_hamilton(get_model, kpt, t_values, compare_isclose, convention):
      """
      Regression test for the Hamiltonian of a simple model.
      """
      model = get_model(*t_values)
      compare_isclose(model.hamilton(kpt, convention=convention))
  
  
  @pytest.mark.parametrize("t_values", T_VALUES)
  @pytest.mark.parametrize("convention", [1, 2])
  def test_parallel_hamilton(get_model, t_values, convention):
      """
      Test that passing multiple k-points to the Hamiltonian gives the
      same results as evaluating them individually.
      """
      model = get_model(*t_values)
      assert_allclose(
          model.hamilton(KPT, convention=convention),
          [model.hamilton(k, convention=convention) for k in KPT],
      )
  
new_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  """Tests for the Hamiltonian method."""
  
  import pytest
  from numpy.testing import assert_allclose
  
  from parameters import KPT, T_VALUES
  
  
  @pytest.mark.parametrize("kpt", KPT)
  @pytest.mark.parametrize("t_values", T_VALUES)
  @pytest.mark.parametrize("convention", [1, 2])
  def test_simple_hamilton(get_model, kpt, t_values, compare_isclose, convention):
      """
      Regression test for the Hamiltonian of a simple model.
      """
      model = get_model(*t_values)
      compare_isclose(model.hamilton(kpt, convention=convention))
  
  
  @pytest.mark.parametrize("t_values", T_VALUES)
  @pytest.mark.parametrize("convention", [1, 2])
  def test_parallel_hamilton(get_model, t_values, convention):
      """
      Test that passing multiple k-points to the Hamiltonian gives the
      same results as evaluating them individually.
      """
      model = get_model(*t_values)
      assert_allclose(
          model.hamilton(KPT, convention=convention),
          [model.hamilton(k, convention=convention) for k in KPT],
      )
  
  
  @pytest.mark.parametrize("convention", ["a", "1", None])
  def test_invalid_convention(get_model, convention):
      """
      Test that giving an invalid 'convention' raises an error.
      """
      model = get_model(t1=0, t2=0.1)
      with pytest.raises(ValueError):
          model.hamilton((0, 0, 0), convention=convention)
  
subject: Add test for invalid 'convention' in hamilton method