def test_zero_potter(): assert_equals(potter([]), 0)
def test_all_the_potters(): assert_equals(potter([1, 2, 3, 4, 5]), 30)
def test_maybe_some_potter(): assert_equals(potter([1, 2, 3, 3]), 3 * 8 * 0.9 + 8)
def test_four_potters(): assert_equals(potter([1, 2, 3, 4]), 8 * 4 * 0.8)
def test_three_potters(): assert_equals(potter([1, 2, 3]), 8 * 3 * 0.9)
def test_two_other_potters(): assert_equals(potter([3, 4]), 15.20)
def test_two_potters(): assert_equals(potter([1, 2]), 15.20)
def test_one_potter(): for i in range(1, 6): assert_equals(potter([i]), 8)