find.py

def find(nums):

    smallest = 9999
    highest = -9999

    for num in nums:
        if num < smallest:
            smallest = num

        if num > highest:
            highest = num


    return smallest, highest

find_test.py

from find import find

def test_decreasing_order():
    min, max = find([29, 28, 27, 26])
    assert min == 26
    assert max == 29

def test_single_number():
    result = find([15])
    assert min == 15
    assert max == 15