* Move no-reactor to pytest-asyncio.
* Unify the style.
* Skip a test that installs a reactor in no-reactor.
* Fix pinned env deps.
* Strict pytest-asyncio mode.
* Add a test for not having pending tasks.
* Refactor TestFeedExporterSignals.
* Refactor FeedExporter.close_spider().
* More engine start/stop robustness.
* Refactor send_catch_log_async(), deprecate send_catch_log_deferred().
* Add pragma: no cover.
* Warn on signal handlers returning a Deferred.
* Make _pending_close_coros an instance attribute.
* Remove an unused function.
* Remove the outdated TODO.
Andrey Rakhmatullin