Challenge 1: Test a String Function — Possible Solution
====================================================================

def is_palindrome(s):
    return s == s[::-1]

def test_is_palindrome_true_case():
    assert is_palindrome("racecar")

def test_is_palindrome_false_case():
    assert not is_palindrome("python")

Running: pytest test_palindrome.py

Output:
test_palindrome.py::test_is_palindrome_true_case PASSED
test_palindrome.py::test_is_palindrome_false_case PASSED

WHY THIS WORKS AS AN ANSWER
------------------------------
is_palindrome(s) reuses the exact s == s[::-1] logic from Course 1,
Chapter 5's own palindrome challenge solution, wrapped in a reusable
function this time instead of a one-off script.

def test_is_palindrome_true_case(): and def test_is_palindrome_false_case():
both reuse this chapter's test_* naming convention exactly — pytest
auto-discovers any function starting with test_ in a test_*.py file,
with no manual registration needed, exactly as the chapter describes.

assert is_palindrome("racecar") reuses the plain assert keyword from
this chapter's opening primer — since is_palindrome("racecar") returns
True, the bare assert (equivalent to assert ... == True) passes
silently. assert not is_palindrome("python") applies Python's not
operator (from Course 1's logical operators) to invert the check —
since is_palindrome("python") returns False, not False is True, so
this assertion also passes.

Two separate test functions are used rather than one, deliberately
mirroring the chapter's own test_add_positive_numbers /
test_add_negative_numbers pair — each test checks exactly one
behavior, so if one case ever breaks, pytest's output reports which
specific case failed rather than a single test covering both.