code: from unittest import TestCase
  
  import numpy as np
  
  from pyecsca.sca import Trace, trim, reverse, pad
  
  
  class EditTests(TestCase):
  
      def setUp(self):
          self._trace = Trace(np.array([10, 20, 30, 40, 50], dtype=np.dtype("i1")))
  
      def test_trim(self):
          result = trim(self._trace, 2)
          self.assertIsNotNone(result)
          np.testing.assert_equal(result.samples, np.array([30, 40, 50], dtype=np.dtype("i1")))
  
          result = trim(self._trace, end=3)
          self.assertIsNotNone(result)
          np.testing.assert_equal(result.samples, np.array([10, 20, 30], dtype=np.dtype("i1")))
  
          with self.assertRaises(ValueError):
              trim(self._trace, 5, 1)
  
      def test_reverse(self):
          result = reverse(self._trace)
          self.assertIsNotNone(result)
          np.testing.assert_equal(result.samples,
                                  np.array([50, 40, 30, 20, 10], dtype=np.dtype("i1")))
  
      def test_pad(self):
          result = pad(self._trace, 2)
          self.assertIsNotNone(result)
          np.testing.assert_equal(result.samples,
                                  np.array([0, 0, 10, 20, 30, 40, 50, 0, 0], dtype=np.dtype("i1")))
  
          result = pad(self._trace, (1, 3))
          self.assertIsNotNone(result)
          np.testing.assert_equal(result.samples,
                                  np.array([0, 10, 20, 30, 40, 50, 0, 0, 0], dtype=np.dtype("i1")))
  
apis: numpy.dtype