feat: add RQ-based webhook dispatch queue and delayed worker

backend/tests/test_webhook_dispatch.py

@@ -0,0 +1,88 @@
+# ruff: noqa: INP001
+"""Webhook queue helper unit tests."""
+
+from __future__ import annotations
+
+from datetime import UTC, datetime
+from uuid import UUID, uuid4
+
+import pytest
+
+from app.services.webhooks.queue import (
+    QueuedWebhookDelivery,
+    dequeue_webhook_delivery,
+    enqueue_webhook_delivery,
+    requeue_if_failed,
+)
+
+
+class _FakeRedis:
+    def __init__(self) -> None:
+        self.values: list[str] = []
+
+    def lpush(self, key: str, value: str) -> None:
+        self.values.insert(0, value)
+
+    def rpop(self, key: str) -> str | None:
+        if not self.values:
+            return None
+        return self.values.pop()
+
+
+@pytest.mark.parametrize("attempts", [0, 1, 2])
+def test_webhook_queue_roundtrip(monkeypatch: pytest.MonkeyPatch, attempts: int) -> None:
+    fake = _FakeRedis()
+
+    def _fake_redis() -> _FakeRedis:
+        return fake
+
+    board_id = uuid4()
+    webhook_id = uuid4()
+    payload_id = uuid4()
+    payload = QueuedWebhookDelivery(
+        board_id=board_id,
+        webhook_id=webhook_id,
+        payload_id=payload_id,
+        payload_event="push",
+        received_at=datetime.now(UTC),
+        attempts=attempts,
+    )
+
+    monkeypatch.setattr("app.services.webhooks.queue._redis_client", _fake_redis)
+    assert enqueue_webhook_delivery(payload)
+
+    dequeued = dequeue_webhook_delivery()
+    assert dequeued is not None
+    assert dequeued.board_id == board_id
+    assert dequeued.webhook_id == webhook_id
+    assert dequeued.payload_id == payload_id
+    assert dequeued.payload_event == "push"
+    assert dequeued.attempts == attempts
+
+
+@pytest.mark.parametrize("attempts", [0, 1, 2, 3])
+def test_requeue_respects_retry_cap(monkeypatch: pytest.MonkeyPatch, attempts: int) -> None:
+    fake = _FakeRedis()
+
+    def _fake_redis() -> _FakeRedis:
+        return fake
+
+    monkeypatch.setattr("app.services.webhooks.queue._redis_client", _fake_redis)
+
+    payload = QueuedWebhookDelivery(
+        board_id=uuid4(),
+        webhook_id=uuid4(),
+        payload_id=uuid4(),
+        payload_event="push",
+        received_at=datetime.now(UTC),
+        attempts=attempts,
+    )
+
+    if attempts >= 3:
+        assert requeue_if_failed(payload) is False
+        assert fake.values == []
+    else:
+        assert requeue_if_failed(payload) is True
+        requeued = dequeue_webhook_delivery()
+        assert requeued is not None
+        assert requeued.attempts == attempts + 1