def test_add(self):
    ' Tests the addition operator.\n        '
    result = (self.v1 + self.v2)
    expected_result = Vector2D((- 1), 1)
    self.assertEqual(result, expected_result)
Tests the addition operator.
def test_add(self):
    ' \n        '
    result = (self.v1 + self.v2)
    expected_result = Vector2D((- 1), 1)
    self.assertEqual(result, expected_result)