import unittest
from summarize import percentile, summarize


class SummaryTests(unittest.TestCase):
    def test_nearest_rank_and_unsorted_input(self):
        self.assertEqual(percentile(list(range(20, 0, -1)), 0.95), 19)
        self.assertEqual(percentile([3, 1, 2], 0.5), 2)

    def test_reject_invalid_samples(self):
        for values in ([], [-1], [float("nan")], [float("inf")]):
            with self.assertRaises(ValueError):
                percentile(values, 0.95)

    def test_paired_overhead_retains_negative_noise(self):
        sample = lambda ms: {"wall_ms": ms, "metrics": {"total_ms": ms / 2}}
        report = {"kind": "synthetic_lexical_index_only", "cases": [{
            "case": "exact", "basic": [sample(4), sample(6)],
            "debug": [sample(3), sample(5)],
        }]}
        result = summarize(report)
        self.assertIsNone(result["production_gate_pass"])
        self.assertEqual(result["cases"][0]["mean_paired_debug_minus_basic_ms"], -1)
        report["cases"][0]["debug"].pop()
        with self.assertRaises(ValueError):
            summarize(report)


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