"""DDG lite fallback: free search must survive an html.duckduckgo.com throttle. The field failure (Alex, 1.5.4): DDG's html endpoint 202-throttled and a subscription-only user (no Gemini/OpenAI key) got "No results / no search backend configured" for every query, free search had a single point of failure. The seal: on html-202 OR html-parse-drift (200 with zero entries), search_ddg falls to lite.duckduckgo.com; only BOTH throttling raises DDGRateLimited. Network is mocked; the lite fixture is the real markup shape captured live 2026-07-07 (single-quoted class attrs, direct hrefs, paired snippet rows). """ import asyncio import pytest import backend.apps.agents.tools.search.search_ddg as SD import backend.apps.agents.tools.search.search_ddg_lite as SDL from backend.apps.agents.tools.browser_http import HttpReply from backend.apps.agents.tools.web import WebSearchTool, DDGRateLimited from backend.apps.agents.tools.search.search_ddg_lite import parse_lite_results P_LITE_BODY = """

1.	Claude Fable \\ Anthropic
	Claude Fable 5 is a real step forward.
2.	TechCrunch story
	Second snippet text.

""" P_HTML_202_BODY = "anomaly detected, challenge page" def p_FakeResp(status: int, text: str) -> HttpReply: return HttpReply(status=status, text=text, content=text.encode(), content_type="text/html", url="https://duckduckgo.example") def p_route(monkeypatch, routes: dict): """Answer per-URL so the html and lite endpoints can behave differently in one test.""" async def p_req(url, **kw): for key, reply in routes.items(): if key in url: return reply raise AssertionError(f"unexpected URL {url}") monkeypatch.setattr(SD, "browser_request", p_req) monkeypatch.setattr(SDL, "browser_request", p_req) def test_lite_parser_on_real_shape(): out = parse_lite_results(P_LITE_BODY, 5) assert "[1] Claude Fable \\ Anthropic" in out assert "https://www.anthropic.com/claude/fable" in out assert "Claude Fable 5 is a real step forward." in out assert "[2] TechCrunch story" in out assert "Second snippet text." in out def test_lite_parser_respects_num_results(): out = parse_lite_results(P_LITE_BODY, 1) assert "[1]" in out and "[2]" not in out def test_html_throttle_falls_to_lite(monkeypatch): p_route(monkeypatch, { "html.duckduckgo.com": p_FakeResp(202, P_HTML_202_BODY), "lite.duckduckgo.com": p_FakeResp(200, P_LITE_BODY), }) out = asyncio.run(WebSearchTool.search_ddg("q", 5)) assert "Claude Fable" in out # lite answered despite html throttle def test_both_throttled_raises_rate_limited(monkeypatch): p_route(monkeypatch, { "html.duckduckgo.com": p_FakeResp(202, P_HTML_202_BODY), "lite.duckduckgo.com": p_FakeResp(202, P_HTML_202_BODY), }) with pytest.raises(DDGRateLimited): asyncio.run(WebSearchTool.search_ddg("q", 5)) def test_html_markup_drift_falls_to_lite(monkeypatch): p_route(monkeypatch, { "html.duckduckgo.com": p_FakeResp(200, "totally new markup"), "lite.duckduckgo.com": p_FakeResp(200, P_LITE_BODY), }) out = asyncio.run(WebSearchTool.search_ddg("q", 5)) assert "Claude Fable" in out # drift didn't silently become "no results"