Use twisted.python.log instead of failure.printTraceback().

tests/CrawlerProcess/asyncio_enabled_reactor_different_loop.py

@@ -2,6 +2,7 @@ import asyncio
 import sys
 
 from twisted.internet import asyncioreactor
+from twisted.python import log
 
 if sys.version_info >= (3, 8) and sys.platform == "win32":
     asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())
@@ -25,5 +26,5 @@ process = CrawlerProcess(
     }
 )
 d = process.crawl(NoRequestsSpider)
-d.addErrback(lambda failure: failure.printTraceback())
+d.addErrback(log.err)
 process.start()

tests/CrawlerProcess/reactor_default_twisted_reactor_select.py

@@ -1,4 +1,5 @@
 from twisted.internet import reactor  # noqa: F401
+from twisted.python import log
 
 import scrapy
 from scrapy.crawler import CrawlerProcess
@@ -18,5 +19,5 @@ process = CrawlerProcess(
 )
 
 d = process.crawl(NoRequestsSpider)
-d.addErrback(lambda failure: failure.printTraceback())
+d.addErrback(log.err)
 process.start()

tests/CrawlerProcess/reactor_select_subclass_twisted_reactor_select.py

@@ -1,5 +1,6 @@
 from twisted.internet.main import installReactor
 from twisted.internet.selectreactor import SelectReactor
+from twisted.python import log
 
 import scrapy
 from scrapy.crawler import CrawlerProcess
@@ -27,5 +28,5 @@ process = CrawlerProcess(
 )
 
 d = process.crawl(NoRequestsSpider)
-d.addErrback(lambda failure: failure.printTraceback())
+d.addErrback(log.err)
 process.start()

tests/CrawlerProcess/twisted_reactor_custom_settings_conflict.py

@@ -1,3 +1,5 @@
+from twisted.python import log
+
 import scrapy
 from scrapy.crawler import CrawlerProcess
 
@@ -18,7 +20,7 @@ class AsyncioReactorSpider(scrapy.Spider):
 
 process = CrawlerProcess()
 d1 = process.crawl(SelectReactorSpider)
-d1.addErrback(lambda failure: failure.printTraceback())
+d1.addErrback(log.err)
 d2 = process.crawl(AsyncioReactorSpider)
-d2.addErrback(lambda failure: failure.printTraceback())
+d2.addErrback(log.err)
 process.start()