"""Acceptance test for time-to-green task T04 (pilot-written 2026-10-30; the protocol names it, does not ship it).

T04: tally: add a `cols <file>` subcommand that prints one header name per line;
exit 2 on a missing file like the others.
Green: python -m unittest tasks.t04_test   (run from the repo root)

Same assertions as the pilot's copy; the only change for the bench is that the regression suite is now
imported from a frozen copy in tasks/ instead of the editable root test file.
"""
from __future__ import annotations

import importlib.util
import io
import os
import tempfile
import unittest

from tasks.regress_tally import HeadTests, StatsTests  # noqa: F401  (collected as regression tests)

ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
_spec = importlib.util.spec_from_file_location(
    "tally_t04", os.path.join(ROOT, "build-a-cli-tool-with-an-agent-from-a-spec.py"))
tally = importlib.util.module_from_spec(_spec)
_spec.loader.exec_module(tally)


def run(argv, text="name,price,qty\nbolt,1.5,10\n"):
    with tempfile.TemporaryDirectory() as tmp:
        path = os.path.join(tmp, "data.csv")
        with open(path, "w", encoding="utf-8", newline="") as fh:
            fh.write(text)
        argv = [path if a == "FILE" else a for a in argv]
        out, err = io.StringIO(), io.StringIO()
        code = tally.main(argv, out=out, err=err)
    return code, out.getvalue(), err.getvalue()


class ColsTests(unittest.TestCase):
    def test_cols_prints_one_header_name_per_line(self):
        code, out, err = run(["cols", "FILE"])
        self.assertEqual(code, 0, err)
        self.assertEqual(out.splitlines(), ["name", "price", "qty"])

    def test_cols_missing_file_exits_2(self):
        out, err = io.StringIO(), io.StringIO()
        code = tally.main(["cols", "no-such-file.csv"], out=out, err=err)
        self.assertEqual(code, 2)
        self.assertEqual(out.getvalue(), "")
        self.assertIn("cannot read", err.getvalue())


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