pr-reviewer/tests/test_endpoints.py

"""Endpoint tests via FastAPI TestClient.

The lazy singletons ``app.main.gh`` / ``app.main.reviewer`` are monkeypatched to
return fakes, so no network and no secrets are required. TestClient uses the
already-installed httpx2, so no extra test deps.
"""

from __future__ import annotations

from typing import Any

import pytest
from fastapi.testclient import TestClient

from app import main as main_mod
from app.github_client import GitHubError


@pytest.fixture
def client() -> TestClient:
    return TestClient(main_mod.app)


class FakeGH:
    def __init__(self) -> None:
        self.posted: dict[str, Any] | None = None

    def search_prs(self) -> list[dict[str, Any]]:
        return [{"owner": "o", "repo": "r", "number": 1, "title": "t"}]

    def whoami(self) -> str:
        return "octocat"

    def pr_diff(self, owner: str, repo: str, number: int) -> str:
        return "diff --git a/x b/x\n+hi\n"

    def submit_review(self, owner, repo, number, body, event) -> dict[str, Any]:
        self.posted = {"event": event, "body": body}
        return {"html_url": "https://github.com/o/r/pull/1#review"}


class FakeReviewer:
    def review(self, pr: dict[str, Any], diff: str) -> dict[str, Any]:
        return {
            "summary": "ok",
            "recommended_event": "COMMENT",
            "_body_markdown": "**Summary:** ok",
            "_diff_seen": diff,
        }


def _patch(monkeypatch, gh=None, reviewer=None):
    if gh is not None:
        monkeypatch.setattr(main_mod, "gh", lambda: gh)
    if reviewer is not None:
        monkeypatch.setattr(main_mod, "reviewer", lambda: reviewer)


# --------------------------------------------------------------------------- #
# /api/config
# --------------------------------------------------------------------------- #


def test_api_config(client: TestClient) -> None:
    r = client.get("/api/config")
    assert r.status_code == 200
    data = r.json()
    assert set(data) == {"org", "filter", "model", "mention_authors"}


# --------------------------------------------------------------------------- #
# /api/prs
# --------------------------------------------------------------------------- #


def test_api_prs_ok(client: TestClient, monkeypatch) -> None:
    _patch(monkeypatch, gh=FakeGH())
    r = client.get("/api/prs")
    assert r.status_code == 200
    data = r.json()
    assert data["me"] == "octocat"
    assert data["prs"][0]["number"] == 1


def test_api_prs_github_error_maps_to_400(client: TestClient, monkeypatch) -> None:
    class BoomGH(FakeGH):
        def search_prs(self):
            raise GitHubError("GitHub 401: Bad credentials")

    _patch(monkeypatch, gh=BoomGH())
    r = client.get("/api/prs")
    assert r.status_code == 400
    assert "Bad credentials" in r.json()["detail"]


# --------------------------------------------------------------------------- #
# /api/review
# --------------------------------------------------------------------------- #


def _review_body() -> dict[str, Any]:
    return {
        "owner": "o",
        "repo": "r",
        "number": 1,
        "title": "t",
        "author": "octocat",
        "body": "b",
    }


def test_api_review_ok(client: TestClient, monkeypatch) -> None:
    _patch(monkeypatch, gh=FakeGH(), reviewer=FakeReviewer())
    r = client.post("/api/review", json=_review_body())
    assert r.status_code == 200
    assert r.json()["review"]["summary"] == "ok"


def test_api_review_github_error_maps_to_400(client: TestClient, monkeypatch) -> None:
    class BoomGH(FakeGH):
        def pr_diff(self, *a):
            raise GitHubError("GitHub 404: Not Found")

    _patch(monkeypatch, gh=BoomGH(), reviewer=FakeReviewer())
    r = client.post("/api/review", json=_review_body())
    assert r.status_code == 400
    assert "Not Found" in r.json()["detail"]


def test_api_review_generic_error_maps_to_500(client: TestClient, monkeypatch) -> None:
    class BoomReviewer:
        def review(self, pr, diff):
            raise ValueError("fireworks exploded")

    _patch(monkeypatch, gh=FakeGH(), reviewer=BoomReviewer())
    r = client.post("/api/review", json=_review_body())
    assert r.status_code == 500
    assert "Review failed" in r.json()["detail"]


# --------------------------------------------------------------------------- #
# /api/revise
# --------------------------------------------------------------------------- #


def test_api_revise_folds_notes_into_diff(client: TestClient, monkeypatch) -> None:
    reviewer = FakeReviewer()
    _patch(monkeypatch, gh=FakeGH(), reviewer=reviewer)
    body = _review_body()
    body["notes"] = "be harsher on error handling"
    r = client.post("/api/revise", json=body)
    assert r.status_code == 200
    seen = r.json()["review"]["_diff_seen"]
    assert "REVIEWER REVISION NOTES" in seen
    assert "be harsher on error handling" in seen


def test_api_revise_generic_error_maps_to_500(client: TestClient, monkeypatch) -> None:
    class BoomReviewer:
        def review(self, pr, diff):
            raise RuntimeError("nope")

    _patch(monkeypatch, gh=FakeGH(), reviewer=BoomReviewer())
    body = _review_body()
    body["notes"] = "x"
    r = client.post("/api/revise", json=body)
    assert r.status_code == 500
    assert "Revision failed" in r.json()["detail"]


# --------------------------------------------------------------------------- #
# /api/post
# --------------------------------------------------------------------------- #


def test_api_post_ok(client: TestClient, monkeypatch) -> None:
    fake = FakeGH()
    _patch(monkeypatch, gh=fake)
    r = client.post(
        "/api/post",
        json={
            "owner": "o",
            "repo": "r",
            "number": 1,
            "body": "lgtm",
            "event": "APPROVE",
        },
    )
    assert r.status_code == 200
    assert r.json()["ok"] is True
    assert fake.posted == {"event": "APPROVE", "body": "lgtm"}


def test_api_post_github_error_maps_to_400(client: TestClient, monkeypatch) -> None:
    class BoomGH(FakeGH):
        def submit_review(self, *a):
            raise GitHubError("Invalid event: LGTM")

    _patch(monkeypatch, gh=BoomGH())
    r = client.post(
        "/api/post",
        json={"owner": "o", "repo": "r", "number": 1, "body": "b", "event": "LGTM"},
    )
    assert r.status_code == 400
    assert "Invalid event" in r.json()["detail"]