new_contents: import unittest
  import numpy as np
  from control.ctrlutil import *
  
  class TestUtils(unittest.TestCase):
      def setUp(self):
          self.mag = np.array([1, 10, 100, 2, 0.1, 0.01])
          self.db = np.array([0, 20, 40, 6.0206, -20, -40])
  
      def check_unwrap_array(self, angle, period=None):
          if period is None:
              angle_mod = angle % (2 * np.pi)
              angle_unwrap = unwrap(angle_mod)
          else:
              angle_mod = angle % period
              angle_unwrap = unwrap(angle_mod, period)
          np.testing.assert_array_almost_equal(angle_unwrap, angle)
  
      def test_unwrap_increasing(self):
          angle = np.linspace(0, 20, 50)
          self.check_unwrap_array(angle)
  
      def test_unwrap_decreasing(self):
          angle = np.linspace(0, -20, 50)
          self.check_unwrap_array(angle)
  
      def test_unwrap_inc_degrees(self):
          angle = np.linspace(0, 720, 50)
          self.check_unwrap_array(angle, 360)
  
      def test_unwrap_dec_degrees(self):
          angle = np.linspace(0, -720, 50)
          self.check_unwrap_array(angle, 360)
  
      def test_unwrap_large_skips(self):
          angle = np.array([0., 4 * np.pi, -2 * np.pi])
          np.testing.assert_array_almost_equal(unwrap(angle), [0., 0., 0.])
  
  def test_suite():
      return unittest.TestLoader().loadTestsFromTestCase(TestUtils)
  
  if __name__ == "__main__":
      unittest.main()
  
subject: Add tests showing problems with ctrlutil.unwrap