conftest.py

import json
import os
import shutil
import subprocess
import sys
import tempfile
from collections.abc import Iterator
from contextlib import contextmanager
from dataclasses import dataclass
from pathlib import Path
from typing import Any, cast

import pytest

from nixpkgs_review.utils import current_system

TEST_ROOT = Path(__file__).parent.resolve()
sys.path.append(str(TEST_ROOT.parent))


@dataclass
class Nixpkgs:
    path: Path
    remote: Path


def run(cmd: list[str | Path]) -> None:
    subprocess.run(cmd, check=True)


def real_nixpkgs() -> str:
    proc = subprocess.run(
        ["nix-instantiate", "--find-file", "nixpkgs"],
        stdout=subprocess.PIPE,
        stderr=subprocess.DEVNULL,
        text=True,
        check=False,
    )
    if proc.returncode == 0:
        return proc.stdout.strip()

    proc = subprocess.run(
        [
            "nix",
            "eval",
            "--extra-experimental-features",
            "nix-command flakes",
            "--raw",
            "nixpkgs#path",
        ],
        check=True,
        stdout=subprocess.PIPE,
        text=True,
    )
    return proc.stdout.strip()


def setup_nixpkgs(target: Path) -> Path:
    shutil.copytree(
        Helpers.root().joinpath("assets/nixpkgs"),
        target,
        dirs_exist_ok=True,
    )

    default_nix = target.joinpath("default.nix")

    text = default_nix.read_text().replace('"@NIXPKGS@"', real_nixpkgs())
    default_nix.write_text(text)

    return target


class Chdir:
    def __init__(self, path: Path | str) -> None:
        self.old_dir = Path.cwd()
        self.new_dir = path

    def __enter__(self) -> None:
        os.chdir(self.new_dir)

    def __exit__(self, *args: object) -> None:
        os.chdir(self.old_dir)


def setup_git(path: Path) -> Nixpkgs:
    os.environ["GIT_AUTHOR_NAME"] = "nixpkgs-review"
    os.environ["GIT_AUTHOR_EMAIL"] = "nixpkgs-review@example.com"
    os.environ["GIT_COMMITTER_NAME"] = "nixpkgs-review"
    os.environ["GIT_COMMITTER_EMAIL"] = "nixpkgs-review@example.com"

    run(["git", "-C", path, "init", "-b", "master"])
    run(["git", "-C", path, "add", "."])
    run(["git", "-C", path, "commit", "-m", "first commit"])

    remote = path.joinpath("remote")
    run(["git", "-C", path, "init", "--bare", str(remote)])
    run(["git", "-C", path, "remote", "add", "origin", str(remote)])
    run(["git", "-C", path, "push", "origin", "HEAD"])
    return Nixpkgs(path=path, remote=remote)


class Helpers:
    @staticmethod
    def root() -> Path:
        return TEST_ROOT

    @staticmethod
    def read_asset(asset: str) -> str:
        return (TEST_ROOT / "assets" / asset).read_text()

    @staticmethod
    def load_report(review_dir: str) -> dict[str, Any]:
        data = (Path(review_dir) / "report.json").read_text()
        return cast(dict[str, Any], json.loads(data))

    @staticmethod
    def assert_built(pkg_name: str, path: str) -> None:
        report = Helpers.load_report(path)
        assert report["result"][current_system()]["built"] == [pkg_name]

    @staticmethod
    @contextmanager
    def save_environ() -> Iterator[None]:
        old = os.environ.copy()
        yield
        os.environ.clear()
        os.environ.update(old)

    @staticmethod
    @contextmanager
    def nixpkgs() -> Iterator[Nixpkgs]:
        with Helpers.save_environ(), tempfile.TemporaryDirectory() as tmpdirname:
            path = Path(tmpdirname)
            nixpkgs_path = path.joinpath("nixpkgs")
            os.environ["XDG_CACHE_HOME"] = str(path.joinpath("cache"))
            setup_nixpkgs(nixpkgs_path)

            with Chdir(nixpkgs_path):
                yield setup_git(nixpkgs_path)


@pytest.fixture
def helpers() -> type[Helpers]:
    return Helpers