Method _write_pgn

tests/arenas/test_chess.py:127–137

(self, file_path, white: str, black: str, result: str)

        pairings_file.write_text(json.dumps(pairings, indent=2))

    def _write_pgn(self, file_path, white: str, black: str, result: str):
        content = (
            """
[Event "FastChess Match"]
[Site "-"]
[Date "2026.01.07"]
[Round "1"]
""".strip()
            + f'\n[White "{white}"]\n[Black "{black}"]\n[Result "{result}"]\n\n'
        )
        file_path.write_text(content)

    def test_player1_wins(self, arena, tmp_log_dir):
        """Alice wins one match; overall winner is Alice."""