litellm/tests/e2e/test_e2e_http.py

"""Harness coverage for the transport's transient-retry policy.

No proxy needed and no ``e2e`` marker: this pins the retry CONTRACT, which is
load-bearing for the whole suite. Only statuses the proxy itself cannot emit
may ever be retried (today exactly 529, Anthropic's overload signal): 429 must
stay unretried because the quota suites assert the proxy's own rate-limit and
budget 429s, and proxy-capable 5xx must stay unretried or an intermittently
failing proxy would slip through green. The fakes satisfy the
RetryableResponse protocol directly, so nothing here imports requests or
monkeypatches anything.
"""

from __future__ import annotations

from collections.abc import Callable, Iterator, Mapping, Sequence
from dataclasses import dataclass
from types import MappingProxyType
from typing import Final

import pytest
from e2e_http import (
    RETRY_ATTEMPTS,
    TRANSIENT_STATUSES,
    NoBody,
    PartialBody,
    Success,
    ValidationError,
    classify,
    request_with_retry,
    streaming_outcome,
    wire_body,
)
from pydantic import BaseModel, TypeAdapter


@dataclass
class FakeResponse:
    status_code: int
    close_calls: int = 0

    def close(self) -> None:
        self.close_calls += 1


@dataclass
class SleepRecorder:
    delays: tuple[float, ...] = ()

    def __call__(self, seconds: float) -> None:
        self.delays += (seconds,)


def _issue_from(responses: Sequence[FakeResponse]) -> Callable[[], FakeResponse]:
    it = iter(responses)
    return lambda: next(it)


class TestTransientRetryPolicy:
    def test_transient_set_is_only_statuses_the_proxy_cannot_emit(self) -> None:
        assert TRANSIENT_STATUSES == frozenset({529})
        assert 429 not in TRANSIENT_STATUSES

    @pytest.mark.parametrize("status", [200, 201, 400, 401, 404, 422, 500, 502, 503, 504])
    def test_non_transient_status_returns_immediately(self, status: int) -> None:
        responses = (FakeResponse(status), FakeResponse(200))
        sleep = SleepRecorder()
        result = request_with_retry(_issue_from(responses), sleep=sleep)
        assert result is responses[0]
        assert sleep.delays == ()
        assert responses[0].close_calls == 0

    def test_429_is_never_retried(self) -> None:
        responses = (FakeResponse(429), FakeResponse(200))
        sleep = SleepRecorder()
        result = request_with_retry(_issue_from(responses), sleep=sleep)
        assert result is responses[0]
        assert sleep.delays == ()
        assert responses[0].close_calls == 0

    def test_overloaded_529_retries_with_backoff_then_returns_the_success(self) -> None:
        responses = (FakeResponse(529), FakeResponse(200))
        sleep = SleepRecorder()
        result = request_with_retry(_issue_from(responses), sleep=sleep)
        assert result is responses[1]
        assert sleep.delays == (0.5,)
        assert responses[0].close_calls == 1
        assert responses[1].close_calls == 0

    def test_persistent_transient_is_bounded_and_returns_the_last_response(self) -> None:
        responses = tuple(FakeResponse(529) for _ in range(RETRY_ATTEMPTS + 1))
        sleep = SleepRecorder()
        result = request_with_retry(_issue_from(responses), sleep=sleep)
        assert result is responses[RETRY_ATTEMPTS - 1]
        assert sleep.delays == (0.5, 1.0)
        assert [r.close_calls for r in responses] == [1, 1, 0, 0]


@dataclass(frozen=True, slots=True)
class FakeSseResponse:
    lines: Sequence[bytes]
    status_code: int = 200
    headers: Mapping[str, str] = MappingProxyType({"content-type": "text/event-stream"})
    text: str = ""

    def iter_lines(self) -> Iterator[bytes]:
        return iter(self.lines)


def _ticking_clock(start: float, step: float) -> Callable[[], float]:
    ticks: Final = iter(range(10_000))
    return lambda: start + step * next(ticks)


class TestStreamEventArrivals:
    def test_each_event_is_stamped_at_the_moment_its_line_arrives(self) -> None:
        resp: Final = FakeSseResponse(
            lines=(
                b"event: message_start",
                b'data: {"type":"message_start"}',
                b"",
                b"event: ping",
                b'data: {"type":"ping"}',
                b"event: content_block_delta",
                b'data: {"type":"content_block_delta"}',
                b"data: [DONE]",
            )
        )

        result: Final = streaming_outcome(resp, True, sent_at=100.0, clock=_ticking_clock(start=100.0, step=0.5))

        assert result.stream_events == [
            '{"type":"message_start"}',
            '{"type":"ping"}',
            '{"type":"content_block_delta"}',
        ]
        assert result.stream_event_arrivals == [0.5, 1.5, 2.5]
        assert result.stream_done
        assert result.chunks == 7

    def test_a_non_streaming_outcome_carries_no_arrivals(self) -> None:
        resp: Final = FakeSseResponse(lines=(), status_code=400, text="bad request")

        result: Final = streaming_outcome(resp, True, sent_at=0.0, clock=_ticking_clock(start=0.0, step=1.0))

        assert result.stream_events == []
        assert result.stream_event_arrivals == []
        assert result.body == "bad request"


class _ServerUpdate(PartialBody):
    server_id: str
    alias: str | None = None
    description: str | None = None


class _ServerCreate(BaseModel):
    alias: str
    description: str | None = None


class TestWireBody:
    """A partial-update body must put exactly the caller's choice on the wire: an
    omitted field stays off it so the route keeps the stored value, and an explicit
    None goes out as JSON null so the route clears it. Plain bodies keep dropping
    None, which is what every create route expects."""

    def test_partial_body_omits_unset_fields_and_sends_explicit_none_as_null(self) -> None:
        assert wire_body(_ServerUpdate(server_id="s1", description=None)) == {"server_id": "s1", "description": None}
        assert wire_body(_ServerUpdate(server_id="s1", alias="renamed")) == {"server_id": "s1", "alias": "renamed"}

    def test_plain_body_drops_none_fields(self) -> None:
        assert wire_body(_ServerCreate(alias="a", description=None)) == {"alias": "a"}


_JSON: Final[TypeAdapter[object]] = TypeAdapter(object)


@dataclass
class FakeJsonResponse:
    """The `classify` view of a response: a status, the raw body bytes, and the
    parse that would raise on an empty one."""

    status_code: int
    content: bytes

    @property
    def ok(self) -> bool:
        return self.status_code < 400

    @property
    def text(self) -> str:
        return self.content.decode()

    def json(self) -> object:
        return _JSON.validate_json(self.content)


class TestClassifyEmptyBody:
    """A delete that answers 202 with no body is a success, not a parse failure:
    the MCP server and toolset delete routes both answer that way, and reading it
    as a failure would hide a delete that did not happen behind one that did."""

    def test_empty_2xx_body_is_a_success(self) -> None:
        result: Final = classify(FakeJsonResponse(status_code=202, content=b""), NoBody)
        assert isinstance(result, Success) and result.status_code == 202

    def test_body_that_is_not_json_is_still_a_validation_failure(self) -> None:
        result: Final = classify(FakeJsonResponse(status_code=200, content=b"<html/>"), NoBody)
        assert isinstance(result, ValidationError)