cloudflare--workers-sdk/packages/vitest-pool-workers/test/unhandled-rejection.test.ts

import dedent from "ts-dedent";
import { test } from "./helpers";

const unhandledRejectionTest = dedent`
	import { it } from "vitest";
	it("triggers unhandled rejection", async () => {
		// Start a promise that will be rejected; don't chain a rejection handler
		// before yielding so it becomes "unhandled" from workerd's perspective.
		Promise.reject(new Error("expected-unhandled-error"));
		await new Promise<void>((resolve) => setTimeout(resolve, 50));
	});
`;

test(
	"unhandled rejection fails the run by default",
	{ timeout: 45_000 },
	async ({ expect, seed, vitestRun }) => {
		await seed({
			"vitest.config.mts": dedent`
				import { cloudflareTest } from "@cloudflare/vitest-pool-workers";
				export default {
					plugins: [cloudflareTest({ miniflare: { compatibilityDate: "2025-12-02", compatibilityFlags: ["nodejs_compat"] } })],
					test: { testTimeout: 30_000 }
				};
			`,
			"index.test.ts": unhandledRejectionTest,
		});
		const result = await vitestRun();
		expect(await result.exitCode).not.toBe(0);
		// The unhandled error is printed to stderr by Vitest
		expect(result.stderr).toMatch("expected-unhandled-error");
	}
);

test(
	"onUnhandledError callback is invoked and can suppress unhandled rejections",
	{ timeout: 45_000 },
	async ({ expect, seed, vitestRun }) => {
		await seed({
			"vitest.config.mts": dedent`
				import { cloudflareTest } from "@cloudflare/vitest-pool-workers";
				export default {
					plugins: [cloudflareTest({ miniflare: { compatibilityDate: "2025-12-02", compatibilityFlags: ["nodejs_compat"] } })],
					test: {
						testTimeout: 30_000,
						onUnhandledError(err) {
							// Errors from workers are serialised plain objects (not Error
							// instances) — match on .message, consistent with standard pools.
							if (err?.message === "expected-unhandled-error") {
								return false;
							}
						},
					},
				};
			`,
			"index.test.ts": unhandledRejectionTest,
		});
		const result = await vitestRun();
		expect(await result.exitCode).toBe(0);
	}
);