#!/usr/bin/env python3
"""Synthetic regression tests for strict source-level coverage accounting."""

from __future__ import annotations

import importlib.util
import unittest


def load_summary_module():
    spec = importlib.util.spec_from_file_location(
        "summarize_test_coverage", "scripts/summarize-test-coverage.py"
    )
    assert spec is not None and spec.loader is not None
    module = importlib.util.module_from_spec(spec)
    spec.loader.exec_module(module)
    return module


SUMMARY = load_summary_module()
SOURCE = "/libs/kaptan-navigation/"
FILENAME = "/repo/libs/kaptan-navigation/src/eskf.rs"


def json_report(*, expansions=None, expanded_file_id=0):
    return {
        "data": [
            {
                "files": [
                    {
                        "filename": FILENAME,
                        "expansions": [] if expansions is None else expansions,
                        # Segments intentionally differ from DA lines: strict
                        # line coverage must not lower its denominator to them.
                        "segments": [[10, 1, 3, True, True, False]],
                        "branches": [
                            [10, 5, 10, 10, 0, 3, 0, expanded_file_id, 4],
                            [10, 5, 10, 10, 2, 0, 0, expanded_file_id, 4],
                            [11, 5, 11, 10, 0, 0, 0, expanded_file_id, 4],
                        ],
                    }
                ]
            }
        ]
    }


LCOV = """SF:/repo/libs/kaptan-navigation/src/eskf.rs
DA:10,0
DA:11,0
end_of_record
SF:/repo/libs/kaptan-navigation/src/eskf.rs
DA:10,3
DA:12,1
end_of_record
"""


class CoverageSummaryTests(unittest.TestCase):
    def test_unions_da_lines_and_full_span_branch_outcomes(self):
        self.assertEqual(
            SUMMARY.coverage_totals(LCOV, json_report(), SOURCE),
            # DA lines: 10 is covered by the second generic instance; 11 is
            # uncovered; 12 is covered. Branch outcomes: the two duplicate
            # source spans cover both outcomes, while line 11 covers neither.
            (2, 3, 2, 4),
        )

    def test_rejects_macro_expansion_records(self):
        with self.assertRaises(SUMMARY.CoverageFormatError):
            SUMMARY.coverage_totals(LCOV, json_report(expansions=[{}]), SOURCE)
        with self.assertRaises(SUMMARY.CoverageFormatError):
            SUMMARY.coverage_totals(LCOV, json_report(expanded_file_id=1), SOURCE)


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