"""三种排序算法找最大值 — 单元测试"""

import pytest

from src.algorithms.find_max_linear import find_max_linear
from src.algorithms.find_max_bubble import find_max_bubble
from src.algorithms.find_max_quickselect import find_max_quickselect

ALL_ALGOS = [find_max_linear, find_max_bubble, find_max_quickselect]


# ── 通用测试（每种算法都跑） ──

@pytest.mark.parametrize("algo", ALL_ALGOS, ids=["linear", "bubble", "quickselect"])
class TestAllAlgorithms:
    def test_normal_list(self, algo):
        assert algo([3, 1, 4, 1, 5, 9, 2, 6]) == 9

    def test_empty_list(self, algo):
        assert algo([]) is None

    def test_single_element(self, algo):
        assert algo([42]) == 42

    def test_negative_numbers(self, algo):
        assert algo([-5, -1, -10, -3]) == -1

    def test_floats(self, algo):
        assert algo([1.5, 2.7, 0.3, 3.14]) == 3.14

    def test_mixed_int_float(self, algo):
        assert algo([1, 2.5, 3, 0.1]) == 3

    def test_duplicate_max(self, algo):
        assert algo([7, 7, 7]) == 7


# ── 一致性测试（同输入三法结果相同） ──

class TestConsistency:
    @pytest.mark.parametrize("nums", [
        [3, 1, 4, 1, 5, 9, 2, 6],
        [-5, -1, -10, -3],
        [1.5, 2.7, 0.3, 3.14],
        [42],
        [7, 7, 7],
        [0, -0.0, 0.0],
        [100, 200, 50, 150, 75],
    ])
    def test_three_algorithms_same_result(self, nums):
        results = [algo(nums) for algo in ALL_ALGOS]
        assert all(r == results[0] for r in results), f"Inconsistent: {results}"

    def test_empty_consistency(self):
        results = [algo([]) for algo in ALL_ALGOS]
        assert all(r is None for r in results)

    def test_does_not_mutate_input(self):
        original = [3, 1, 4, 1, 5, 9, 2, 6]
        for algo in ALL_ALGOS:
            nums = list(original)
            algo(nums)
            assert nums == original, f"{algo.__name__} mutated input"