signal-bot/tests/test_tool_imports.py

# Copyright (c) 2026 Krzysztof Rudnicki. MIT licence.
"""Every script under tool/ imports, and the launcher answers --help.

This exists because ``tool/tagger.py`` shipped an unconditional ImportError
and survived two releases with it: commit 48957a1 renamed
``pack.default_dir`` to ``default_dirs`` and missed the caller. Nothing could
have caught it. ``tool/`` is outside ``--cov`` in pyproject.toml, mypy ran
with ``args: [signal_bot, fake_signal]``, and ruff lints these files but
cannot resolve a name in another module.

So this is deliberately the cheapest possible test: import each file and, for
the one with a CLI, run it. It adds no coverage burden -- ``tests/`` is not
measured -- and no module-scope ImportError can survive it.
"""

from __future__ import annotations

import importlib.util
import sys
from pathlib import Path

import pytest

from signal_bot.external import run

TOOL = Path(__file__).resolve().parent.parent / "tool"


def _modules() -> list[Path]:
    """Every Python file under tool/, so a new one is covered automatically."""
    return sorted(path for path in TOOL.glob("*.py") if path.name != "__init__.py")


def test_there_is_something_to_check() -> None:
    # Guards against the glob silently matching nothing and the whole file
    # passing vacuously.
    assert _modules()


def _load(stem: str) -> object:
    """Import one tool/ module by path, the way the parametrised test does."""
    spec = importlib.util.spec_from_file_location(f"_probe_{stem}", TOOL / f"{stem}.py")
    assert spec is not None
    assert spec.loader is not None
    module = importlib.util.module_from_spec(spec)
    spec.loader.exec_module(module)
    return module


@pytest.mark.parametrize("path", _modules(), ids=lambda path: path.name)
def test_the_module_imports(path: Path) -> None:
    spec = importlib.util.spec_from_file_location(f"_tool_{path.stem}", path)
    assert spec is not None
    assert spec.loader is not None
    module = importlib.util.module_from_spec(spec)
    sys.modules[spec.name] = module
    # tool/ is a directory of scripts, not a package, and a couple of them
    # import a sibling by bare name. That resolves in real use -- running
    # "python tool/x.py" puts tool/ at sys.path[0] -- so the harness has to
    # reproduce it rather than the scripts having to work around it.
    sys.path.insert(0, str(TOOL))
    try:
        spec.loader.exec_module(module)
    finally:
        sys.path.remove(str(TOOL))
        sys.modules.pop(spec.name, None)


def test_the_launcher_answers_help() -> None:
    # Through signal_bot.external, like every other subprocess here: S603 is
    # suppressed for exactly one file and widening it is what that entry
    # exists to prevent.
    result = run([sys.executable, str(TOOL / "web.py"), "--help"])
    assert result.ok, result.stderr
    for flag in ("--import", "--untagged", "--dry-run"):
        assert flag in result.stdout


def test_the_bootstrap_reports_what_this_interpreter_cannot_import() -> None:
    # The whole decision rests on this: an interpreter that can already
    # import everything must be left alone, or every run pays for a venv it
    # does not need.
    bootstrap = _load("venv_bootstrap")
    assert bootstrap.missing() == []
    assert bootstrap.missing(("definitely_not_a_real_module",)) == ["definitely_not_a_real_module"]
    # A name that is not importable *and* not a valid spec query has to be
    # reported, not raised: find_spec raises ValueError for some of them.
    assert bootstrap.missing((".relative",)) == [".relative"]


def test_the_bootstrap_module_is_stdlib_only() -> None:
    # It runs before .venv exists, so a third-party import here would be the
    # same bug one level down.
    source = (TOOL / "venv_bootstrap.py").read_text(encoding="utf-8")
    for banned in ("import fastapi", "import httpx", "import uvicorn", "from signal_bot"):
        assert banned not in source


def test_the_bootstrap_only_installs_when_the_venv_cannot_already_do_it(
    tmp_path: Path,
) -> None:
    # Measured bug: ensure() tested the *current* interpreter to decide both
    # whether to re-exec and whether to install. The interpreter you typed
    # never grows a fastapi, so every single launch reinstalled the project
    # before re-execing. The two decisions are separate.
    bootstrap = _load("venv_bootstrap")
    bootstrap.VENV_PYTHON = tmp_path / "nonexistent" / "python"
    assert bootstrap.ready() is False
    bootstrap.VENV_PYTHON = Path(sys.executable)
    assert bootstrap.ready(("sys",)) is True
    assert bootstrap.ready(("definitely_not_a_real_module",)) is False