Tests for extensions.debug and extensions.memdebug.

tests/test_extension_debug.py

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+from __future__ import annotations
+
+import logging
+import os
+import signal
+import sys
+import threading
+from typing import TYPE_CHECKING
+from unittest import mock
+
+import pytest
+
+from scrapy.extensions.debug import Debugger, StackTraceDump
+from scrapy.spiders import Spider
+from scrapy.utils.spider import DefaultSpider
+from scrapy.utils.test import get_crawler
+from tests.utils.decorators import coroutine_test
+
+if TYPE_CHECKING:
+    from collections.abc import Generator
+
+
+@pytest.fixture(autouse=True)
+def preserve_signal_handlers() -> Generator[None]:
+    """Restore the signal handlers that the extensions replace."""
+    signums = [
+        getattr(signal, name)
+        for name in ("SIGUSR2", "SIGQUIT")
+        if hasattr(signal, name)
+    ]
+    handlers = {signum: signal.getsignal(signum) for signum in signums}
+    yield
+    for signum, handler in handlers.items():
+        signal.signal(signum, handler)
+
+
+class SignalSpider(Spider):
+    name = "signal_spider"
+    start_urls = ["data:,"]
+
+    def parse(self, response):
+        os.kill(os.getpid(), signal.SIGUSR2)
+        return []
+
+
+@pytest.mark.skipif(
+    sys.platform == "win32", reason="SIGUSR2 and SIGQUIT are POSIX-only"
+)
+def test_stacktracedump_installs_signal_handlers() -> None:
+    crawler = get_crawler()
+    ext = StackTraceDump.from_crawler(crawler)
+    assert signal.getsignal(signal.SIGUSR2) == ext.dump_stacktrace  # pylint: disable=comparison-with-callable
+    assert signal.getsignal(signal.SIGQUIT) == ext.dump_stacktrace  # pylint: disable=comparison-with-callable
+
+
+def test_stacktracedump_works_without_signal_support(
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    # simulate win32 platforms, which don't support SIGUSR signals
+    monkeypatch.delattr(signal, "SIGUSR2", raising=False)
+    ext = StackTraceDump.from_crawler(get_crawler())
+    assert isinstance(ext, StackTraceDump)
+
+
+def test_stacktracedump_dump_stacktrace(caplog: pytest.LogCaptureFixture) -> None:
+    crawler = get_crawler()
+    crawler.engine = mock.Mock()
+    ext = StackTraceDump.from_crawler(crawler)
+    spider = DefaultSpider()
+    with caplog.at_level(logging.INFO, logger="scrapy.extensions.debug"):
+        ext.dump_stacktrace(0, None)
+    assert len(caplog.records) == 1
+    message = caplog.records[0].getMessage()
+    assert "Dumping stack trace and engine status" in message
+    assert "Execution engine status" in message
+    assert "Live References" in message
+    assert type(spider).__name__ in message
+    assert "# Thread: MainThread" in message
+    assert getattr(caplog.records[0], "crawler", None) is crawler
+
+
+def test_stacktracedump_thread_stacks() -> None:
+    ext = StackTraceDump.from_crawler(get_crawler())
+    stop = threading.Event()
+    thread = threading.Thread(target=stop.wait, name="dump-test-thread")
+    thread.start()
+    try:
+        stacks = ext._thread_stacks()
+    finally:
+        stop.set()
+        thread.join()
+    assert "# Thread: MainThread" in stacks
+    assert "# Thread: dump-test-thread" in stacks
+
+
+@pytest.mark.skipif(sys.platform == "win32", reason="SIGUSR2 is POSIX-only")
+@coroutine_test
+async def test_stacktracedump_dumps_on_signal(caplog: pytest.LogCaptureFixture) -> None:
+    settings = {
+        "EXTENSIONS": {"scrapy.extensions.debug.StackTraceDump": 0},
+        "LOG_LEVEL": "INFO",
+    }
+    crawler = get_crawler(spidercls=SignalSpider, settings_dict=settings)
+    with caplog.at_level(logging.INFO, logger="scrapy.extensions.debug"):
+        await crawler.crawl_async()
+    assert len(caplog.records) == 1
+    message = caplog.records[0].getMessage()
+    assert "Dumping stack trace and engine status" in message
+    assert "engine.spider.name" in message
+    assert "signal_spider" in message
+
+
+@pytest.mark.skipif(sys.platform == "win32", reason="SIGUSR2 is POSIX-only")
+def test_debugger_installs_signal_handler() -> None:
+    ext = Debugger()
+    assert signal.getsignal(signal.SIGUSR2) == ext._enter_debugger  # pylint: disable=comparison-with-callable
+
+
+def test_debugger_works_without_signal_support(monkeypatch: pytest.MonkeyPatch) -> None:
+    # simulate win32 platforms, which don't support SIGUSR signals
+    monkeypatch.delattr(signal, "SIGUSR2", raising=False)
+    ext = Debugger()
+    assert isinstance(ext, Debugger)
+
+
+def test_debugger_enter_debugger(monkeypatch: pytest.MonkeyPatch) -> None:
+    pdb_cls = mock.Mock()
+    monkeypatch.setattr("scrapy.extensions.debug.Pdb", pdb_cls)
+    ext = Debugger()
+    frame = sys._getframe()
+    ext._enter_debugger(0, frame)
+    pdb_cls.return_value.set_trace.assert_called_once_with(frame.f_back)

tests/test_extension_memdebug.py

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+from __future__ import annotations
+
+import gc
+
+import pytest
+
+from scrapy.exceptions import NotConfigured
+from scrapy.extensions.memdebug import MemoryDebugger
+from scrapy.utils.spider import DefaultSpider
+from scrapy.utils.test import get_crawler
+from scrapy.utils.trackref import object_ref
+from tests.utils.decorators import coroutine_test
+
+
+def test_disabled_by_default() -> None:
+    with pytest.raises(NotConfigured):
+        MemoryDebugger.from_crawler(get_crawler())
+
+
+def test_spider_closed_sets_stats() -> None:
+    crawler = get_crawler(settings_dict={"MEMDEBUG_ENABLED": True})
+    ext = MemoryDebugger.from_crawler(crawler)
+
+    class TrackedObject(object_ref):
+        pass
+
+    class CollectedObject(object_ref):
+        pass
+
+    tracked = [TrackedObject(), TrackedObject()]
+    CollectedObject()
+
+    ext.spider_closed(DefaultSpider(), "finished")
+
+    assert crawler.stats
+    assert crawler.stats.get_value("memdebug/gc_garbage_count") == len(gc.garbage)
+    assert crawler.stats.get_value("memdebug/live_refs/TrackedObject") == len(tracked)
+    assert crawler.stats.get_value("memdebug/live_refs/CollectedObject") is None
+
+
+@coroutine_test
+async def test_crawl_sets_stats() -> None:
+    crawler = get_crawler(DefaultSpider, settings_dict={"MEMDEBUG_ENABLED": True})
+    await crawler.crawl_async()
+    assert crawler.stats
+    assert crawler.stats.get_value("memdebug/gc_garbage_count") is not None
+    assert crawler.stats.get_value("memdebug/live_refs/DefaultSpider") == 1