music-mirror/tests/conftest.py

import os
import shutil
import subprocess
import sys

import pytest

# Ensure the project root is on sys.path when running tests.
ROOT = os.path.dirname(os.path.dirname(__file__))
if ROOT not in sys.path:
    sys.path.insert(0, ROOT)


@pytest.fixture(scope="session", autouse=True)
def require_ffmpeg():
    """The tests exercise real encodes; there is little point faking them."""
    for tool in ("ffmpeg", "ffprobe"):
        if shutil.which(tool) is None:
            pytest.skip(f"{tool} is not on PATH", allow_module_level=True)


@pytest.fixture
def tight_umask():
    """Run a test under a umask that would otherwise make the mirror private."""
    previous = os.umask(0o077)
    yield
    os.umask(previous)


@pytest.fixture
def owner_hostile_umask():
    """Return a callable applying a umask that masks off the owner's read bit.

    Unusual, but it is what produces a mirror tree of mode 0300 -- writable and
    enterable, unreadable to the very process that built it. Applied on demand
    rather than for the whole test, because the source library is built by
    something else entirely and the same umask would make the test's own
    fixtures unreadable before the run under test even started.
    """
    previous = os.umask(0o022)
    yield lambda: os.umask(0o477)
    os.umask(previous)


@pytest.fixture
def make_flac():
    """Return a factory writing a short tagged FLAC file."""

    def factory(path, title="Test Title", artist="Test Artist", album="Test Album", seconds=1):
        path.parent.mkdir(parents=True, exist_ok=True)
        subprocess.run(
            [
                "ffmpeg",
                "-nostdin",
                "-hide_banner",
                "-loglevel",
                "error",
                "-y",
                "-f",
                "lavfi",
                "-i",
                f"sine=frequency=440:duration={seconds}",
                "-metadata",
                f"title={title}",
                "-metadata",
                f"artist={artist}",
                "-metadata",
                f"album={album}",
                "-metadata",
                "track=3",
                str(path),
            ],
            check=True,
            capture_output=True,
        )
        return path

    return factory


@pytest.fixture
def make_cover():
    """Return a factory writing a small JPEG beside an album's tracks."""

    def factory(path):
        path.parent.mkdir(parents=True, exist_ok=True)
        subprocess.run(
            ["ffmpeg", "-nostdin", "-hide_banner", "-loglevel", "error", "-y",
             "-f", "lavfi", "-i", "color=c=red:s=64x64:d=1", "-frames:v", "1", str(path)],
            check=True,
            capture_output=True,
        )
        return path

    return factory


@pytest.fixture
def probe_tag():
    """Return a helper reading a single metadata tag from a file."""

    def reader(path, tag):
        completed = subprocess.run(
            [
                "ffprobe",
                "-v",
                "error",
                "-show_entries",
                f"format_tags={tag}",
                "-of",
                "default=noprint_wrappers=1:nokey=1",
                str(path),
            ],
            check=True,
            capture_output=True,
            text=True,
        )
        return completed.stdout.strip()

    return reader