"""Load unittest files without letting an empty selection report success."""

import argparse
from concurrent.futures import ThreadPoolExecutor
import importlib.util
import subprocess
from pathlib import Path
import sys
import unittest


def suite_for(path, test_name=None):
    path = Path(path).resolve()
    sys.path.insert(0, str(path.parent))
    spec = importlib.util.spec_from_file_location(path.stem, path)
    assert spec is not None and spec.loader is not None
    module = importlib.util.module_from_spec(spec)
    sys.modules[path.stem] = module
    spec.loader.exec_module(module)
    loader = unittest.TestLoader()
    suite = (
        loader.loadTestsFromName(test_name, module)
        if test_name
        else loader.loadTestsFromModule(module)
    )
    if suite.countTestCases() == 0:
        raise ValueError(f"no tests collected from {path}")
    return suite


def run_file(path):
    result = subprocess.run(
        [sys.executable, __file__, path], capture_output=True, text=True
    )
    print(f"{'ok' if result.returncode == 0 else 'FAILED'} {path}", file=sys.stderr)
    if result.returncode:
        print(result.stdout + result.stderr, file=sys.stderr)
    return result.returncode == 0


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument("--jobs", type=int, default=1)
    parser.add_argument("paths", nargs="+")
    args = parser.parse_args()
    if len(args.paths) > 1:
        with ThreadPoolExecutor(max_workers=max(1, args.jobs)) as pool:
            outcomes = list(pool.map(run_file, args.paths))
        return 0 if all(outcomes) else 1
    try:
        suite = suite_for(args.paths[0])
    except ValueError as error:
        print(error, file=sys.stderr)
        return 1
    return 0 if unittest.TextTestRunner(verbosity=2).run(suite).wasSuccessful() else 1


if __name__ == "__main__":
    sys.exit(main())