text: import unittest
  from lib.insertion_sort import insertion_sort
  
  class InsertionSortTest(unittest.TestCase):
      def setUp(self):
          self.arr = []
      
      def test_insertion_sort(self):
          # Already sorted
          self.arr = [1, 2, 3, 4, 5]
          self.assertEqual(insertion_sort(self.arr), [1, 2, 3, 4, 5])
          # Already reverse sorted
          self.arr = [5, 4, 3, 2, 1]
          self.assertEqual(insertion_sort(self.arr), [1, 2, 3, 4, 5])
          # Not sorted
          self.arr = [4, 2, 1, 5, 3]
          self.assertEqual(insertion_sort(self.arr), [1, 2, 3, 4, 5])