new_contents: import numpy as np
  import sfs
  import pytest
  
  
  linear_cases = [
      ((3, 1), [[-1, 0, 0], [0, 0, 0], [1, 0, 0]]),
      ((2, 1), [[-0.5, 0, 0], [0.5, 0, 0]]),
      ((1, 1), [[0, 0, 0]]),
      ((3, 0.5), [[-0.5, 0, 0], [0, 0, 0], [0.5, 0, 0]]),
      ((2, 1, [0.5, 2, 3]), [[0, 2, 3], [1, 2, 3]]),
      ((2, 1, np.array([0.5, 2, 3])), [[0, 2, 3], [1, 2, 3]]),
      ((2, 1, np.array([[0.5, 2, 3]])), [[0, 2, 3], [1, 2, 3]]),
      ((2, 1, np.array([[0.5, 2, 3]]).transpose()), [[0, 2, 3], [1, 2, 3]]),
      ((2, 1, np.matrix([[0.5, 2, 3]])), [[0, 2, 3], [1, 2, 3]]),
      ((2, 1, np.matrix([[0.5, 2, 3]]).transpose()), [[0, 2, 3], [1, 2, 3]]),
  ]
  
  
  @pytest.mark.parametrize("args, result", linear_cases)
  def test_linear(args, result):
      a = sfs.array.linear(*args)
      assert a.dtype == np.float64
      assert np.all(a == result)
  
  
  def test_linear_named_args():
      a = sfs.array.linear(N=2, dx=0.5, center=[0.25, 1, 2])
      assert np.all(a == [[0, 1, 2], [0.5, 1, 2]])
  
subject: Add a first test file