harness_zbt/backend/tests/test_backend_supervisor.py

from collections.abc import Sequence

from zbt.commands.serve import run_backend_supervisor


class FakeProcess:
    def __init__(self, return_code: int | None) -> None:
        self._return_code = return_code
        self.terminated = False
        self.killed = False

    def poll(self) -> int | None:
        return self._return_code

    def terminate(self) -> None:
        self.terminated = True
        self._return_code = 0

    def wait(self, timeout: float | None = None) -> int:
        del timeout
        return 0 if self._return_code is None else self._return_code

    def kill(self) -> None:
        self.killed = True
        self._return_code = -9


def test_unified_backend_starts_api_and_worker_and_stops_peer_on_exit() -> None:
    api = FakeProcess(return_code=0)
    worker = FakeProcess(return_code=None)
    launched_roles: list[str] = []

    def launch(role: str, command: Sequence[str]) -> FakeProcess:
        assert command
        launched_roles.append(role)
        return api if role == "api" else worker

    result = run_backend_supervisor(
        launch=launch,
        api_command=("python", "-m", "uvicorn", "zbt.main:app"),
        worker_command=("python", "-m", "zbt.commands.run_refund_worker"),
        output=lambda _: None,
        poll_interval_seconds=0,
    )

    assert result == 0
    assert launched_roles == ["api", "refund-worker"]
    assert worker.terminated is True
    assert worker.killed is False


def test_unified_backend_fails_when_refund_worker_exits_unexpectedly() -> None:
    api = FakeProcess(return_code=None)
    worker = FakeProcess(return_code=0)

    def launch(role: str, command: Sequence[str]) -> FakeProcess:
        del command
        return api if role == "api" else worker

    result = run_backend_supervisor(
        launch=launch,
        api_command=("api",),
        worker_command=("worker",),
        output=lambda _: None,
        poll_interval_seconds=0,
    )

    assert result == 1
    assert api.terminated is True