"""Make the test suite runnable on machines without Tk system libraries.

``utils.filedialogs`` imports tkinter at module level, and the CI runner
lacks the Tk shared libraries (``import tkinter`` fails on a missing
``libtk8.6.so``). Since pytest imports every test module at collection
time — including the deselected ``test_filedialogs_live.py`` — a minimal
stub is registered in ``sys.modules`` here, before any test module is
imported, whenever tkinter is not importable.

The hermetic tests in ``test_filedialogs.py`` mock every tkinter
touchpoint anyway, so the stub is never actually used.
"""

import sys
import types

try:
    import tkinter  # noqa: F401
except ImportError:
    _tk_stub = types.ModuleType("tkinter")
    _filedialog_stub = types.ModuleType("tkinter.filedialog")

    def _tk_unavailable(*args, **kwargs):
        raise AssertionError("real tkinter was called without a display")

    _tk_stub.Tk = _tk_unavailable
    _tk_stub.filedialog = _filedialog_stub
    _filedialog_stub.askdirectory = _tk_unavailable
    _filedialog_stub.askopenfilename = _tk_unavailable
    sys.modules["tkinter"] = _tk_stub
    sys.modules["tkinter.filedialog"] = _filedialog_stub