old_contents: import pytest
  
  from zellij.postulates import fbetween, overlap
  
  
  @pytest.mark.parametrize("a, b, c, result", [
      (1, 2, 3, True),
      (3, 2, 1, True),
      (2, 1, 3, False),
      (1, 2, 1, False),
      (1, 1, 0, True),
      (0, 1, 1, True),
      (1, 1, 1, True),
      (0, -1.5265566588595902e-16, 0.0, True),
      (0, -1e-16, 1, True),
  ])
  def test_fbetween(a, b, c, result):
      assert fbetween(a, b, c) == result
  
  
  @pytest.mark.parametrize("s1, e1, s2, e2, result", [
      # Simple cases.
      (0, 5, 1, 6, True),
      (0, 5, 10, 15, False),
      # start and end might be reversed.
      (5, 0, 1, 6, True),
      (0, 5, 6, 1, True),
      (5, 0, 6, 1, True),
      # Ranges touch.
      (0, 5, 5, 10, True),
  ])
  def test_overlap(s1, e1, s2, e2, result):
      assert overlap(s1, e1, s2, e2) == result
  
new_contents: import pytest
  
  from zellij.postulates import adjacent_pairs, fbetween, overlap
  
  
  @pytest.mark.parametrize("seq, result", [
      ([1, 2, 3, 4], [(1, 2), (2, 3), (3, 4)]),
      ([1, 2, 3], [(1, 2), (2, 3)]),
      ([1, 2], [(1, 2)]),
      ([1], []),
      ([], []),
  ])
  def test_adjacent_pairs(seq, result):
      assert list(adjacent_pairs(seq)) == result
  
  
  @pytest.mark.parametrize("a, b, c, result", [
      (1, 2, 3, True),
      (3, 2, 1, True),
      (2, 1, 3, False),
      (1, 2, 1, False),
      (1, 1, 0, True),
      (0, 1, 1, True),
      (1, 1, 1, True),
      (0, -1.5265566588595902e-16, 0.0, True),
      (0, -1e-16, 1, True),
  ])
  def test_fbetween(a, b, c, result):
      assert fbetween(a, b, c) == result
  
  
  @pytest.mark.parametrize("s1, e1, s2, e2, result", [
      # Simple cases.
      (0, 5, 1, 6, True),
      (0, 5, 10, 15, False),
      # start and end might be reversed.
      (5, 0, 1, 6, True),
      (0, 5, 6, 1, True),
      (5, 0, 6, 1, True),
      # Ranges touch.
      (0, 5, 5, 10, True),
  ])
  def test_overlap(s1, e1, s2, e2, result):
      assert overlap(s1, e1, s2, e2) == result
  
subject: Test adjacent_pairs