old_contents: import pytest
  import numpy as np
  import qutip
  
  
  @pytest.mark.parametrize('num_mat', [1, 2, 3, 5])
  def test_simdiag(num_mat):
      N = 10
  
      U = qutip.rand_unitary(N)
      commuting_matrices = [U * qutip.qdiags(np.random.rand(N), 0) * U.dag()
                            for _ in range(num_mat)]
      all_evals, evecs = qutip.simdiag(commuting_matrices)
  
      for matrix, evals in zip(commuting_matrices, all_evals):
          for eval, evec in zip(evals, evecs):
              assert matrix * evec == evec * eval
  
  
  @pytest.mark.parametrize('num_mat', [1, 2, 3, 5])
  def test_simdiag_no_evals(num_mat):
      N = 10
  
      U = qutip.rand_unitary(N)
      commuting_matrices = [U * qutip.qdiags(np.random.rand(N), 0) * U.dag()
                            for _ in range(num_mat)]
      evecs = qutip.simdiag(commuting_matrices, evals=False)
  
      for matrix in commuting_matrices:
          for evec in evecs:
              Mvec = matrix * evec
              eval = Mvec.full()[0,0] / evec.full()[0,0]
              assert matrix * evec == evec * eval
  
  
  def test_simdiag_degen():
      N = 10
      U = qutip.rand_unitary(N)
      matrix = U * qutip.qdiags([0,0,0,1,1,1,2,2,3,4], 0) * U.dag()
      evals, evecs = qutip.simdiag([matrix])
  
      for eval, evec in zip(evals[0], evecs):
          assert matrix * evec == evec * eval
  
  
  def test_simdiag_no_input():
      with pytest.raises(ValueError):
          qutip.simdiag([])
  
  
  @pytest.mark.parametrize(['ops', 'error'], [
      pytest.param([qutip.basis(5,0)], 'square', id="Not square"),
      pytest.param([qutip.qeye(5), qutip.qeye(3)], 'shape', id="shape mismatch"),
      pytest.param([qutip.destroy(5)], 'Hermitian', id="Non Hermitian"),
      pytest.param([qutip.sigmax(), qutip.sigmay()], 'commute', id="Not commuting"),
  ])
  def test_simdiag_errors(ops, error):
      with pytest.raises(TypeError) as err:
          qutip.simdiag(ops)
      assert error in str(err.value)
  
new_contents: import pytest
  import numpy as np
  import qutip
  
  
  @pytest.mark.parametrize('num_mat', [1, 2, 3, 5])
  def test_simdiag(num_mat):
      N = 10
  
      U = qutip.rand_unitary(N)
      commuting_matrices = [U * qutip.qdiags(np.random.rand(N), 0) * U.dag()
                            for _ in range(num_mat)]
      all_evals, evecs = qutip.simdiag(commuting_matrices)
  
      for matrix, evals in zip(commuting_matrices, all_evals):
          for eval, evec in zip(evals, evecs):
              assert matrix * evec == evec * eval
  
  
  @pytest.mark.parametrize('num_mat', [1, 2, 3, 5])
  def test_simdiag_no_evals(num_mat):
      N = 10
  
      U = qutip.rand_unitary(N)
      commuting_matrices = [U * qutip.qdiags(np.random.rand(N), 0) * U.dag()
                            for _ in range(num_mat)]
      evecs = qutip.simdiag(commuting_matrices, evals=False)
  
      for matrix in commuting_matrices:
          for evec in evecs:
              Mvec = matrix * evec
              eval = Mvec.norm() / evec.norm()
              assert matrix * evec == evec * eval
  
  
  def test_simdiag_degen():
      N = 10
      U = qutip.rand_unitary(N)
      matrix = U * qutip.qdiags([0,0,0,1,1,1,2,2,3,4], 0) * U.dag()
      evals, evecs = qutip.simdiag([matrix])
  
      for eval, evec in zip(evals[0], evecs):
          assert matrix * evec == evec * eval
  
  
  def test_simdiag_no_input():
      with pytest.raises(ValueError):
          qutip.simdiag([])
  
  
  @pytest.mark.parametrize(['ops', 'error'], [
      pytest.param([qutip.basis(5,0)], 'square', id="Not square"),
      pytest.param([qutip.qeye(5), qutip.qeye(3)], 'shape', id="shape mismatch"),
      pytest.param([qutip.destroy(5)], 'Hermitian', id="Non Hermitian"),
      pytest.param([qutip.sigmax(), qutip.sigmay()], 'commute', id="Not commuting"),
  ])
  def test_simdiag_errors(ops, error):
      with pytest.raises(TypeError) as err:
          qutip.simdiag(ops)
      assert error in str(err.value)
  
subject: Update qutip/tests/test_simdiag.py