Remove some potential dead-code.

examples/embedding/inprocess_qtconsole.py

@@ -1,54 +1,24 @@
 """An in-process qt console app."""
 import os
-import sys
 
 import tornado
 from IPython.lib import guisupport
 from qtconsole.inprocess import QtInProcessKernelManager
 from qtconsole.rich_ipython_widget import RichIPythonWidget
 
+assert tornado.version_info >= (6, 1)
+
 
 def print_process_id():
     """Print the process id."""
     print("Process ID is:", os.getpid())
 
 
-def init_asyncio_patch():
-    """set default asyncio policy to be compatible with tornado
-    Tornado 6 (at least) is not compatible with the default
-    asyncio implementation on Windows
-    Pick the older SelectorEventLoopPolicy on Windows
-    if the known-incompatible default policy is in use.
-    do this as early as possible to make it a low priority and overridable
-    ref: https://github.com/tornadoweb/tornado/issues/2608
-    FIXME: if/when tornado supports the defaults in asyncio,
-           remove and bump tornado requirement for py38
-    """
-    if (
-        sys.platform.startswith("win")
-        and sys.version_info >= (3, 8)
-        and tornado.version_info < (6, 1)
-    ):
-        import asyncio
-
-        try:
-            from asyncio import WindowsProactorEventLoopPolicy, WindowsSelectorEventLoopPolicy
-        except ImportError:
-            pass
-            # not affected
-        else:
-            if type(asyncio.get_event_loop_policy()) is WindowsProactorEventLoopPolicy:
-                # WindowsProactorEventLoopPolicy is not compatible with tornado 6
-                # fallback to the pre-3.8 default of Selector
-                asyncio.set_event_loop_policy(WindowsSelectorEventLoopPolicy())
-
-
 def main():
     """The main entry point."""
     # Print the ID of the main process
     print_process_id()
 
-    init_asyncio_patch()
     app = guisupport.get_app_qt4()
 
     # Create an in-process kernel

ipykernel/kernelapp.py

@@ -657,7 +657,7 @@ def _init_asyncio_patch(self):
                where asyncio.ProactorEventLoop supports add_reader and friends.
 
         """
-        if sys.platform.startswith("win") and sys.version_info >= (3, 8):
+        if sys.platform.startswith("win"):
             import asyncio
 
             try:

tests/test_eventloop.py

@@ -7,7 +7,6 @@
 import time
 
 import pytest
-import tornado
 
 from ipykernel.eventloops import (
     enable_gui,
@@ -16,7 +15,7 @@
     loop_tk,
 )
 
-from .utils import execute, flush_channels, start_new_kernel
+from .utils import flush_channels, start_new_kernel
 
 KC = KM = None
 
@@ -61,25 +60,6 @@ def _setup_env():
 """
 
 
-@pytest.mark.skipif(tornado.version_info < (5,), reason="only relevant on tornado 5")
-def test_asyncio_interrupt():
-    assert KM is not None
-    assert KC is not None
-    flush_channels(KC)
-    msg_id, content = execute("%gui asyncio", KC)
-    assert content["status"] == "ok", content
-
-    flush_channels(KC)
-    msg_id, content = execute(async_code, KC)
-    assert content["status"] == "ok", content
-
-    KM.interrupt_kernel()
-
-    flush_channels(KC)
-    msg_id, content = execute(async_code, KC)
-    assert content["status"] == "ok"
-
-
 windows_skip = pytest.mark.skipif(os.name == "nt", reason="causing failures on windows")
 
 

tests/test_kernel.py

@@ -212,7 +212,7 @@ def test_sys_path_profile_dir():
 
 @flaky(max_runs=3)
 @pytest.mark.skipif(
-    sys.platform == "win32" or (sys.platform == "darwin" and sys.version_info >= (3, 8)),
+    sys.platform == "win32" or (sys.platform == "darwin"),
     reason="subprocess prints fail on Windows and MacOS Python 3.8+",
 )
 def test_subprocess_print():
@@ -267,7 +267,7 @@ def test_subprocess_noprint():
 
 @flaky(max_runs=3)
 @pytest.mark.skipif(
-    sys.platform == "win32" or (sys.platform == "darwin" and sys.version_info >= (3, 8)),
+    (sys.platform == "win32") or (sys.platform == "darwin"),
     reason="subprocess prints fail on Windows and MacOS Python 3.8+",
 )
 def test_subprocess_error():