How to Calculate Powers of 2 in Python

The challenge

Complete the function that takes a non-negative integer n as input, and returns a list of all the powers of 2 with the exponent ranging from 0 to n (inclusive).

Examples

n = 0  ==> [1]        # [2^0]
n = 1  ==> [1, 2]     # [2^0, 2^1]
n = 2  ==> [1, 2, 4]  # [2^0, 2^1, 2^2]

The solution in Python code

Option 1:

def powers_of_two(n):
    out = []
    for i in range(n+1):
        out.append(2**i)
    return out

Option 2:

def powers_of_two(n):
    return [2**i for i in range(n+1)]

Option 3:

def powers_of_two(n):
    return [1<<x for x in range(n + 1)]

Test cases to validate our solution

import test
from solution import powers_of_two

@test.describe("Fixed Tests")
def fixed_tests():
    @test.it('Basic Test Cases')
    def basic_test_cases():
        test.assert_equals(powers_of_two(0), [1])
        test.assert_equals(powers_of_two(1), [1, 2])
        test.assert_equals(powers_of_two(4), [1, 2, 4, 8, 16])