Square elements using list comprehensions

Write a function that receives a list of integers and returns a list with all the elements squared using list comprehensions.

square_elements([1, 2, 3, 4, 5]) == [1, 4, 9, 16, 25]
import unittest

class SquareElementsTestCase(unittest.TestCase):
    def test_square_elements(self):
        self.assertEqual(square_elements([1, 2, 3, 4, 5]),
                         [1, 4, 9, 16, 25])

    def test_square_elements_repeated(self):
        self.assertEqual(square_elements([1, 1, 2, 2, 3, 3]),
                         [1, 1, 4, 4, 9, 9])

    def test_square_elements_empty_list(self):
        self.assertEqual(square_elements([]), [])