Add tests that check asyncio support.

conftest.py

@@ -27,3 +27,7 @@ def pytest_collection_modifyitems(session, config, items):
             items[:] = [item for item in items if isinstance(item, Flake8Item)]
     except ImportError:
         pass
+
+@pytest.fixture()
+def reactor_pytest(request):
+    request.cls.reactor_pytest = request.config.getoption("--reactor")

tests/test_commands.py

@@ -9,6 +9,7 @@ from tempfile import mkdtemp
 from contextlib import contextmanager
 from threading import Timer
 
+from pytest import mark
 from twisted.trial import unittest
 
 import scrapy
@@ -178,6 +179,7 @@ class MiscCommandsTest(CommandTest):
         self.assertEqual(0, self.call('list'))
 
 
+@mark.usefixtures('reactor_pytest')
 class RunSpiderCommandTest(CommandTest):
 
     debug_log_spider = """
@@ -295,6 +297,11 @@ class BadSpider(scrapy.Spider):
         self.assertIn("start_requests", log)
         self.assertIn("badspider.py", log)
 
+    def test_asyncio_supported(self):
+        if self.reactor_pytest == 'asyncio':
+            log = self.get_log(self.debug_log_spider)
+            self.assertIn("DEBUG: Asyncio support enabled", log)
+
 
 class BenchCommandTest(CommandTest):
 

tests/test_crawler.py

@@ -1,14 +1,16 @@
 import logging
 import warnings
 
+from pytest import raises, mark
+from testfixtures import LogCapture
 from twisted.internet import defer
 from twisted.trial import unittest
-from pytest import raises
 
 import scrapy
 from scrapy.crawler import Crawler, CrawlerRunner, CrawlerProcess
 from scrapy.settings import Settings, default_settings
 from scrapy.spiderloader import SpiderLoader
+from scrapy.utils.asyncio import is_asyncio_supported
 from scrapy.utils.log import configure_logging, get_scrapy_root_handler
 from scrapy.utils.spider import DefaultSpider
 from scrapy.utils.misc import load_object
@@ -203,6 +205,15 @@ class NoRequestsSpider(scrapy.Spider):
         return []
 
 
+class AsyncioSpider(scrapy.Spider):
+    name = 'asyncio'
+
+    def start_requests(self):
+        self.logger.info('Asyncio support: %s', is_asyncio_supported())
+        return []
+
+
+@mark.usefixtures('reactor_pytest')
 class CrawlerRunnerHasSpider(unittest.TestCase):
 
     @defer.inlineCallbacks
@@ -245,3 +256,10 @@ class CrawlerRunnerHasSpider(unittest.TestCase):
         yield runner.crawl(NoRequestsSpider)
 
         self.assertEqual(runner.bootstrap_failed, True)
+
+    @defer.inlineCallbacks
+    def test_asyncio_supported(self):
+        runner = CrawlerRunner()
+        with LogCapture() as log:
+            yield runner.crawl(AsyncioSpider)
+            log.check_present(('asyncio', 'INFO', 'Asyncio support: %s' % (self.reactor_pytest == 'asyncio')))

tests/test_utils_asyncio.py

@@ -0,0 +1,17 @@
+from unittest import TestCase
+
+from pytest import mark
+
+from scrapy.utils.asyncio import is_asyncio_supported, install_asyncio_reactor
+
+
+@mark.usefixtures('reactor_pytest')
+class AsyncioTest(TestCase):
+
+    def test_is_asyncio_supported(self):
+        # the result should depend only on the pytest --reactor argument
+        self.assertEquals(is_asyncio_supported(), self.reactor_pytest == 'asyncio')
+
+    def test_install_asyncio_reactor(self):
+        # this should do nothing
+        install_asyncio_reactor()

tox.ini

@@ -106,3 +106,9 @@ deps =
     {[testenv]deps}
     reppy
     robotexclusionrulesparser
+
+[testenv:py38-no-asyncio]
+basepython = python3.8
+deps = {[testenv]deps}
+commands =
+    py.test --cov=scrapy --cov-report= --reactor=default {posargs:scrapy tests}