pi-gui/test/recovery-supervisor.test.js

import assert from "node:assert/strict";
import test from "node:test";
import { createRecoverySupervisor } from "../src/bridge/recovery-supervisor.js";

test("restarts after bounded exponential delays and stops after exhaustion", async () => {
	const delays = [];
	const states = [];
	let starts = 0;
	const supervisor = createRecoverySupervisor({
		start: async () => ({ attempt: ++starts }),
		maxAttempts: 2,
		delayForAttempt: (attempt) => attempt * 100,
		sleep: async (delay) => delays.push(delay),
		onState: (state) => states.push(state),
	});

	assert.deepEqual(await supervisor.handleUnexpectedExit(), { attempt: 1 });
	assert.deepEqual(await supervisor.handleUnexpectedExit(), { attempt: 2 });
	assert.equal(await supervisor.handleUnexpectedExit(), undefined);
	assert.deepEqual(delays, [100, 200]);
	assert.deepEqual(
		states.map(({ state, attempt }) => ({ state, attempt })),
		[
			{ state: "recovering", attempt: 1 },
			{ state: "healthy", attempt: 1 },
			{ state: "recovering", attempt: 2 },
			{ state: "healthy", attempt: 2 },
			{ state: "failed", attempt: 2 },
		],
	);
});

test("restarts failed launches within the same bounded recovery budget", async () => {
	let starts = 0;
	const supervisor = createRecoverySupervisor({
		start: async () => {
			starts += 1;
			if (starts === 1) throw new Error("temporary spawn failure");
			return { attempt: starts };
		},
		maxAttempts: 2,
		delayForAttempt: () => 0,
		sleep: async () => {},
	});

	assert.deepEqual(await supervisor.handleUnexpectedExit(), { attempt: 2 });
	assert.equal(starts, 2);
});

test("cancels scheduled recovery when stopped", async () => {
	let resolveSleep;
	const supervisor = createRecoverySupervisor({
		start: async () => assert.fail("must not restart after stop"),
		delayForAttempt: () => 1,
		sleep: () =>
			new Promise((resolve) => {
				resolveSleep = resolve;
			}),
	});

	const recovering = supervisor.handleUnexpectedExit();
	supervisor.stop();
	resolveSleep();
	assert.equal(await recovering, undefined);
});