Improve test coverage for crawler.py

tests/AsyncCrawlerProcess/dns_resolver_deprecated.py

@@ -0,0 +1,31 @@
+import sys
+
+import scrapy
+from scrapy.crawler import AsyncCrawlerProcess
+from scrapy.settings import Settings
+
+
+class NoRequestsSpider(scrapy.Spider):
+    name = "no_request"
+
+    async def start(self):
+        return
+        yield
+
+
+settings = Settings()
+# The deprecated DNS_RESOLVER setting, set above its default priority so that
+# AsyncCrawlerProcess._setup_reactor() emits the deprecation warning.
+settings.set("DNS_RESOLVER", "scrapy.resolver.CachingThreadedResolver", priority=10)
+if len(sys.argv) > 1 and sys.argv[1] == "twisted-wins":
+    # TWISTED_DNS_RESOLVER at a higher priority takes precedence over the
+    # deprecated DNS_RESOLVER setting.
+    settings.set(
+        "TWISTED_DNS_RESOLVER",
+        "scrapy.resolver.CachingThreadedResolver",
+        priority=20,
+    )
+
+process = AsyncCrawlerProcess(settings)
+process.crawl(NoRequestsSpider)
+process.start()

tests/CrawlerProcess/dns_resolver_deprecated.py

@@ -0,0 +1,31 @@
+import sys
+
+import scrapy
+from scrapy.crawler import CrawlerProcess
+from scrapy.settings import Settings
+
+
+class NoRequestsSpider(scrapy.Spider):
+    name = "no_request"
+
+    async def start(self):
+        return
+        yield
+
+
+settings = Settings()
+# The deprecated DNS_RESOLVER setting, set above its default priority so that
+# CrawlerProcess._setup_reactor() emits the deprecation warning.
+settings.set("DNS_RESOLVER", "scrapy.resolver.CachingThreadedResolver", priority=10)
+if len(sys.argv) > 1 and sys.argv[1] == "twisted-wins":
+    # TWISTED_DNS_RESOLVER at a higher priority takes precedence over the
+    # deprecated DNS_RESOLVER setting.
+    settings.set(
+        "TWISTED_DNS_RESOLVER",
+        "scrapy.resolver.CachingThreadedResolver",
+        priority=20,
+    )
+
+process = CrawlerProcess(settings)
+process.crawl(NoRequestsSpider)
+process.start()

tests/test_crawler.py

@@ -687,6 +687,22 @@ def test_create_crawler_instance_consistent_with_spider_class() -> None:
     assert pre_built.settings["FOO"] == "runner"
 
 
+@pytest.mark.parametrize("runner_cls", [AsyncCrawlerRunner, CrawlerRunner])
+def test_create_crawler_rejects_spider_object(
+    runner_cls: type[CrawlerRunnerBase],
+) -> None:
+    runner = runner_cls()
+    with pytest.raises(ValueError, match="cannot be a spider object"):
+        runner.create_crawler(DefaultSpider())
+
+
+@pytest.mark.parametrize("runner_cls", [AsyncCrawlerRunner, CrawlerRunner])
+def test_crawl_rejects_spider_object(runner_cls: type[CrawlerRunnerBase]) -> None:
+    runner = runner_cls()
+    with pytest.raises(ValueError, match="cannot be a spider object"):
+        runner.crawl(DefaultSpider())
+
+
 class ExceptionSpider(scrapy.Spider):
     name = "exception"
 

tests/test_crawler_subprocess.py

@@ -126,6 +126,16 @@ class TestCrawlerProcessSubprocessBase(ScriptRunnerMixin):
         assert "TimeoutError" not in log
         assert "scrapy.exceptions.CannotResolveHostError" not in log
 
+    def test_dns_resolver_deprecated(self) -> None:
+        log = self.run_script("dns_resolver_deprecated.py")
+        assert "Spider closed (finished)" in log
+        assert "The DNS_RESOLVER setting is deprecated" in log
+
+    def test_dns_resolver_deprecated_twisted_dns_resolver(self) -> None:
+        log = self.run_script("dns_resolver_deprecated.py", "twisted-wins")
+        assert "Spider closed (finished)" in log
+        assert "The DNS_RESOLVER setting is deprecated" in log
+
     def test_twisted_reactor_asyncio(self) -> None:
         log = self.run_script("twisted_reactor_asyncio.py")
         assert "Spider closed (finished)" in log