scrapy/tests/test_spider_start.py

from __future__ import annotations

import warnings
from asyncio import sleep
from typing import Any

import pytest
from testfixtures import LogCapture

from scrapy import Spider, signals
from scrapy.exceptions import ScrapyDeprecationWarning
from scrapy.utils.defer import maybe_deferred_to_future
from scrapy.utils.test import get_crawler

from .utils import twisted_sleep
from .utils.decorators import coroutine_test

SLEEP_SECONDS = 0.1

ITEM_A = {"id": "a"}
ITEM_B = {"id": "b"}


class TestMain:
    async def _test_spider(
        self, spider: type[Spider], expected_items: list[Any] | None = None
    ) -> None:
        actual_items = []
        expected_items = [] if expected_items is None else expected_items

        def track_item(item, response, spider):
            actual_items.append(item)

        crawler = get_crawler(spider)
        crawler.signals.connect(track_item, signals.item_scraped)
        await crawler.crawl_async()
        assert crawler.stats
        assert crawler.stats.get_value("finish_reason") == "finished"
        assert actual_items == expected_items

    @coroutine_test
    async def test_start_urls(self):
        class TestSpider(Spider):
            name = "test"
            start_urls = ["data:,"]

            async def parse(self, response):
                yield ITEM_A

        with warnings.catch_warnings():
            warnings.simplefilter("error")
            await self._test_spider(TestSpider, [ITEM_A])

    @coroutine_test
    async def test_start(self):
        class TestSpider(Spider):
            name = "test"

            async def start(self):
                yield ITEM_A

        with warnings.catch_warnings():
            warnings.simplefilter("error")
            await self._test_spider(TestSpider, [ITEM_A])

    @coroutine_test
    async def test_start_subclass(self):
        class BaseSpider(Spider):
            async def start(self):
                yield ITEM_A

        class TestSpider(BaseSpider):
            name = "test"

        with warnings.catch_warnings():
            warnings.simplefilter("error")
            await self._test_spider(TestSpider, [ITEM_A])

    @coroutine_test
    async def test_deprecated(self):
        class TestSpider(Spider):
            name = "test"

            def start_requests(self):
                yield ITEM_A

        with pytest.warns(ScrapyDeprecationWarning):
            await self._test_spider(TestSpider, [ITEM_A])

    @coroutine_test
    async def test_deprecated_subclass(self):
        class BaseSpider(Spider):
            def start_requests(self):
                yield ITEM_A

        class TestSpider(BaseSpider):
            name = "test"

        # The warning must be about the base class and not the subclass.
        with pytest.warns(ScrapyDeprecationWarning, match="BaseSpider"):
            await self._test_spider(TestSpider, [ITEM_A])

    @coroutine_test
    async def test_universal(self):
        class TestSpider(Spider):
            name = "test"

            async def start(self):
                yield ITEM_A

            def start_requests(self):
                yield ITEM_B

        with warnings.catch_warnings():
            warnings.simplefilter("error")
            await self._test_spider(TestSpider, [ITEM_A])

    @coroutine_test
    async def test_universal_subclass(self):
        class BaseSpider(Spider):
            async def start(self):
                yield ITEM_A

            def start_requests(self):
                yield ITEM_B

        class TestSpider(BaseSpider):
            name = "test"

        with warnings.catch_warnings():
            warnings.simplefilter("error")
            await self._test_spider(TestSpider, [ITEM_A])

    @coroutine_test
    async def test_start_deprecated_super(self):
        class TestSpider(Spider):
            name = "test"

            async def start(self):
                for item_or_request in super().start_requests():
                    yield item_or_request

        with pytest.warns(
            ScrapyDeprecationWarning, match=r"use Spider\.start\(\) instead"
        ) as messages:
            await self._test_spider(TestSpider, [])
        assert messages[0].filename.endswith("test_spider_start.py")

    async def _test_start(self, start_, expected_items=None):
        class TestSpider(Spider):
            name = "test"
            start = start_

        await self._test_spider(TestSpider, expected_items)

    @pytest.mark.only_asyncio
    @coroutine_test
    async def test_asyncio_delayed(self):
        async def start(spider):
            await sleep(SLEEP_SECONDS)
            yield ITEM_A

        await self._test_start(start, [ITEM_A])

    @pytest.mark.requires_reactor  # needs a reactor for twisted_sleep()
    @coroutine_test
    async def test_twisted_delayed(self):
        async def start(spider):
            await maybe_deferred_to_future(twisted_sleep(SLEEP_SECONDS))
            yield ITEM_A

        await self._test_start(start, [ITEM_A])

    # Exceptions

    @coroutine_test
    async def test_deprecated_non_generator_exception(self):
        class TestSpider(Spider):
            name = "test"

            def start_requests(self):
                raise RuntimeError

        with (
            LogCapture() as log,
            pytest.warns(
                ScrapyDeprecationWarning,
                match=r"defines the deprecated start_requests\(\) method",
            ),
        ):
            await self._test_spider(TestSpider, [])

        assert "in start_requests\n    raise RuntimeError" in str(log)