"""Stdlib tests for the permutation test. No Chroma."""
from __future__ import annotations

import unittest

from eval.pvalue import paired_permutation


class PermutationTests(unittest.TestCase):
    def test_identical_is_not_significant(self) -> None:
        a = [1.0, 0.5, 0.0, 1.0]
        r = paired_permutation(a, list(a), n_resamples=200, seed=0)
        self.assertEqual(r["Diff(A-B)"], 0.0)
        self.assertFalse(r["significant"])

    def test_large_shift_is_significant(self) -> None:
        a = [1.0] * 20
        b = [0.0] * 20
        r = paired_permutation(a, b, n_resamples=500, seed=0)
        self.assertTrue(r["significant"])
        self.assertLess(r["p_value"], 0.05)


if __name__ == "__main__":
    unittest.main()