[jay23606]

Summary

Normalize Windows path separators before filtering files by client in PySUS.query, so FTP files are not dropped on Windows.

Fixes #372

Validation

• python -m pytest pysus/tests/api/test_client.py -q — 51 passed.
• Regression gate — the focused test failed on both clean-base worktrees and passed on both fix worktrees.
• Black, isort, Flake8, and git diff --check passed.

[ArthurFachel]

Thanks for this. I was looking at #372 too and found the same pattern in a second place that this PR doesn't touch yet: _fetch_origin_direct in pysus/api/_impl/source.py (around line 266), which is the source="origin" path.

files = [f for f in files if str(f.path).startswith(prefix)]

With only the client.py change, PySUS.query(client=...) keeps the Windows paths, but _fetch_origin_direct then filters them out again, so the empty result remains on that path.

A regression test in the same style, for TestFetchOriginDirect in pysus/tests/api/test_source.py. It fails on master and passes once that line normalizes the path:

def test_prefix_filter_windows_path(self):
    """Regression for #372: backslash paths must still match prefix."""
    from pathlib import PureWindowsPath

    from pysus.api._impl.source import _fetch_origin_direct

    matching = self._file(
        PureWindowsPath("public/data/ftp/sinasc/DNSE2010.parquet")
    )
    other = self._file(PureWindowsPath("elsewhere/b.parquet"))
    pysus = self._make_pysus([matching, other])
    result = self._run(
        _fetch_origin_direct(
            pysus, "sinasc", None, "SE", 2010, None, "FTP", None,
            False, False, download=False, _bag=True,
        )
    )
    assert result == [matching]

Feel free to fold it into this PR. If it helps, a small shared helper (e.g. as_posix() for PurePath, str() otherwise) would keep both filters consistent. Happy to open a follow-up PR instead if you'd rather keep this one focused.