test: skip tkinter scheduler tests on PyPy (all platforms)

The module creates `tkinter.Tk()` at import time. During PyPy interpreter
shutdown, `_tkinter/app.py`'s `__del__` calls `threading.notify_all`,
which can abort the process with `Fatal Python error: Aborted`. When
this happens inside an xdist worker it takes the worker down and fails
whichever unrelated test happens to be running (e.g. test_case_three),
showing up as a non-deterministic CI failure.

The skip guard previously only covered macOS+PyPy; extend it to all
PyPy platforms so the Linux PyPy job stops flaking.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: dbrattli

changes.md

@@ -2,6 +2,11 @@
 
 ## Unreleased
 
+- CI: Skip `tests/test_scheduler/test_mainloop/test_tkinterscheduler.py` on
+  PyPy (all platforms). The module creates a Tk root at import time; PyPy's
+  `_tkinter` finalizer calls `threading.notify_all` during interpreter
+  shutdown and aborts the xdist worker, failing whichever unrelated test
+  was running. Previously guarded only on macOS+PyPy.
 - Fix: `reactivex.timer(duetime, period)` now correctly resets the initial
   delay on each resubscription (e.g. via `repeat()`). Previously `nonlocal
   duetime` in the subscribe closure mutated the shared outer variable so

tests/test_scheduler/test_mainloop/test_tkinterscheduler.py

@@ -1,5 +1,4 @@
 import os
-import platform
 import sys
 import unittest
 from datetime import timedelta
@@ -10,12 +9,14 @@
 from reactivex.internal.basic import default_now
 from reactivex.scheduler.mainloop import TkinterScheduler
 
-# Skip entire module on PyPy + macOS due to threading issues with Tkinter
-# Error: "Tcl_AsyncDelete: async handler deleted by the wrong thread"
-# This occurs when pytest-xdist tries to parallelize tests that use Tkinter
-if platform.system() == "Darwin" and hasattr(sys, "pypy_version_info"):
+# Skip entire module on PyPy due to Tkinter interpreter/finalizer issues.
+# On macOS: "Tcl_AsyncDelete: async handler deleted by the wrong thread".
+# On Linux: PyPy's _tkinter app __del__ calls threading.notify_all during
+# interpreter shutdown, which aborts the xdist worker and fails whichever
+# test it was running.
+if hasattr(sys, "pypy_version_info"):
     pytest.skip(
-        "Tkinter tests are incompatible with PyPy on macOS", allow_module_level=True
+        "Tkinter tests are incompatible with PyPy", allow_module_level=True
     )
 
 tkinter = pytest.importorskip("tkinter")