import manacher


def test_empty():
    assert manacher.longest_palindrome("") == ""


def test_single():
    assert manacher.longest_palindrome("a") == "a"


def test_known():
    cases = {
        "babad": "bab",
        "cbbd": "bb",
        "a": "a",
        "ac": "a",
        "racecar": "racecar",
        "abacdfgdcaba": "aba",
        "aaaa": "aaaa",
        "abacaba": "abacaba",
    }
    for s, exp in cases.items():
        got = manacher.longest_palindrome(s)
        # accept any maximal-length palindrome
        assert len(got) == len(exp), (s, got, exp)
        assert got == got[::-1]


def test_all_same():
    s = "x" * 1000
    assert manacher.longest_palindrome(s) == s


def test_no_palindrome_longer_than_one():
    s = "abcdef"
    assert len(manacher.longest_palindrome(s)) == 1


def test_even_center():
    assert manacher.longest_palindrome("abba") == "abba"


def test_distinct_substrings_smoke():
    out = manacher.all_palindromic_substrings("aaa")
    assert set(out) == {"a", "aa", "aaa"}