Drop pytest-twisted, use Scrapy code to install the reactor.

conftest.py

@@ -2,6 +2,8 @@ from pathlib import Path
 
 import pytest
 
+from scrapy.utils.reactor import install_reactor
+
 from tests.keys import generate_keys
 
 
@@ -40,6 +42,14 @@ def pytest_collection_modifyitems(session, config, items):
         pass
 
 
+def pytest_addoption(parser):
+    parser.addoption(
+        "--reactor",
+        default="default",
+        choices=["default", "asyncio"],
+    )
+
+
 @pytest.fixture(scope='class')
 def reactor_pytest(request):
     if not request.cls:
@@ -55,5 +65,10 @@ def only_asyncio(request, reactor_pytest):
         pytest.skip('This test is only run with --reactor=asyncio')
 
 
+def pytest_configure(config):
+    if config.getoption("--reactor") == "asyncio":
+        install_reactor("twisted.internet.asyncioreactor.AsyncioSelectorReactor")
+
+
 # Generate localhost certificate files, needed by some tests
 generate_keys()

pytest.ini

@@ -18,7 +18,6 @@ addopts =
     --ignore=docs/topics/stats.rst
     --ignore=docs/topics/telnetconsole.rst
     --ignore=docs/utils
-twisted = 1
 markers =
     only_asyncio: marks tests as only enabled when --reactor=asyncio is passed
 flake8-max-line-length = 119

tests/requirements-py3.txt

@@ -2,10 +2,8 @@
 attrs
 dataclasses; python_version == '3.6'
 pyftpdlib
-# https://github.com/pytest-dev/pytest-twisted/issues/93
-pytest != 5.4, != 5.4.1
+pytest
 pytest-cov
-pytest-twisted >= 1.11
 pytest-xdist
 sybil >= 1.3.0  # https://github.com/cjw296/sybil/issues/20#issuecomment-605433422
 testfixtures