old_contents: """
  Unit test for the Virtual Figure 8 Bot.
  Ensure the the Figure 8 Bot hits certain checkpoints in its loop.
  """
  
  import math
  import unittest
  
  from tests.virtual8bot import Virtual8Bot
  
  def dist(x1, y1, x2, y2):
      """
      Return the Euclidean distance between two points.
      """
      return math.sqrt((x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1))
  
  class TestVirtual8BotPhysics(unittest.TestCase):
      """
      Unit test for the Virtual Figure 8 Bot.
      """
  
      def test_simulation(self):
          """
          Test simulation
          """
          bot = Virtual8Bot()
  
          m = 1.0 + math.sqrt(2) / 2.0
          checkpoints = [
              (0, 0),
              (1, 0),
              (m, m),
              (0, 1),
              (0, 0),
              (0, -1),
              (-m, -m),
              (-1, 0),
              (0, 0),
          ]
          threshold = 0.1
          next_checkpoint = 0
          t = 0
          dt = 0.01
  
          while next_checkpoint < len(checkpoints) and t < 15:
              bot.run(dt)
              t += dt
              state = bot.get_state()
              cx, cy = checkpoints[next_checkpoint]
              if dist(cx, cy, state.x, state.y) < threshold:
                  next_checkpoint += 1
  
          self.assertEqual(next_checkpoint, len(checkpoints))
  
  if __name__ == "__main__":
      unittest.main()
  
new_contents: """
  Unit test for the Virtual Figure 8 Bot.
  Ensure the the Figure 8 Bot hits certain checkpoints in its loop.
  """
  
  import math
  import unittest
  
  from tests.virtual8bot import Virtual8Bot
  
  def dist(x1, y1, x2, y2):
      """
      Returns:
          float: The Euclidean distance between two points.
      """
      return math.sqrt((x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1))
  
  class TestVirtual8BotPhysics(unittest.TestCase):
      """
      Unit test for the Virtual Figure 8 Bot.
      """
  
      def test_simulation(self):
          """
          Test simulation
          """
          bot = Virtual8Bot()
  
          m = 1.0 + math.sqrt(2) / 2.0
          checkpoints = [
              (0, 0),
              (1, 0),
              (m, m),
              (0, 1),
              (0, 0),
              (0, -1),
              (-m, -m),
              (-1, 0),
              (0, 0),
          ]
          threshold = 0.1
          next_checkpoint = 0
          t = 0
          dt = 0.01
  
          while next_checkpoint < len(checkpoints) and t < 15:
              bot.run(dt)
              t += dt
              state = bot.get_state()
              cx, cy = checkpoints[next_checkpoint]
              if dist(cx, cy, state.x, state.y) < threshold:
                  next_checkpoint += 1
  
          self.assertEqual(next_checkpoint, len(checkpoints))
  
  if __name__ == "__main__":
      unittest.main()
  
subject: Fix up function doc