fix: make vitest-pool-workers not crash with scripts that have Workflows (#8208)

* fix: make vitest-pool-workers not crash with scripts that have Workflows

Because `vitest-pool-workers` uses its runner worker as the entrypoint
and not the user provided worker. The user provided worker is loaded
AFAICT though eval (`vitest-pool-workers` enables eval) so we need, at
startup time, to add the required entrypoints and make them dynamically
call the user one.

Not only that, if you try to create a workflow instance it would throw a
`isolated storage` error - I suspect that is this caused by engine still
being active at the end of the test (since workflows are async, not in
the request path, and might take undefinite time to complete).

In order to fix this, I've bypassed the isolated storage check for
workflows internal DOs. I wonder if there might be collisions between
test files if there are any concurrency regarding test files (aka
`singleWorker` is false) - I think that this is fine to do, the point of
this PR is not to make workflows really testable yet but to at least
to make `vitest-pool-workers` **not** crash if a user includes a
workflow in the worker definition.

* chore: add proper readme

* chore: remove isolatedStorage bypass and error out early if isolated storage is used

* chore: add suggestions

* chore: moar test

* Apply suggestions from code review

Co-authored-by: Pete Bacon Darwin <[email protected]>

* Apply suggestions from code review

Co-authored-by: Pete Bacon Darwin <[email protected]>

* stream logs

* no more hanging

* Revert "stream logs"

This reverts commit dfecf63.

---------

Co-authored-by: Pete Bacon Darwin <[email protected]>
Co-authored-by: Samuel Macleod <[email protected]>

Author: 3 people

.changeset/vast-stars-dig.md

@@ -0,0 +1,5 @@
+---
+"@cloudflare/vitest-pool-workers": patch
+---
+
+Make vitest-pool-workers not crash when a workflow is defined

fixtures/vitest-pool-workers-examples/workflows/README.md

@@ -0,0 +1,4 @@
+# 🔁 workflows
+
+Unit testing of workflows themselves is not possible yet - but you can still
+trigger them in unit tests.

fixtures/vitest-pool-workers-examples/workflows/src/env.d.ts

@@ -0,0 +1,3 @@
+interface Env {
+	TEST_WORKFLOW: Workflow;
+}

fixtures/vitest-pool-workers-examples/workflows/src/index.ts

@@ -0,0 +1,27 @@
+import {
+	WorkerEntrypoint,
+	WorkflowEntrypoint,
+	WorkflowEvent,
+	WorkflowStep,
+} from "cloudflare:workers";
+
+export class TestWorkflow extends WorkflowEntrypoint<Env> {
+	async run(_event: Readonly<WorkflowEvent<unknown>>, step: WorkflowStep) {
+		return "test-workflow";
+	}
+}
+
+export default class TestNamedEntrypoint extends WorkerEntrypoint<Env> {
+	async fetch(request: Request) {
+		const maybeId = new URL(request.url).searchParams.get("id");
+		if (maybeId !== null) {
+			const instance = await this.env.TEST_WORKFLOW.get(maybeId);
+
+			return Response.json(await instance.status());
+		}
+
+		const workflow = await this.env.TEST_WORKFLOW.create();
+
+		return new Response(JSON.stringify({ id: workflow.id }));
+	}
+}

fixtures/vitest-pool-workers-examples/workflows/src/tsconfig.json

@@ -0,0 +1,4 @@
+{
+	"extends": "../../tsconfig.workerd.json",
+	"include": ["./**/*.ts"]
+}

fixtures/vitest-pool-workers-examples/workflows/test/env.d.ts

@@ -0,0 +1,6 @@
+declare module "cloudflare:test" {
+	// Controls the type of `import("cloudflare:test").env`
+	interface ProvidedEnv extends Env {
+		TEST_WORKFLOW: Workflow;
+	}
+}

fixtures/vitest-pool-workers-examples/workflows/test/integration-self.test.ts

@@ -0,0 +1,22 @@
+import { SELF } from "cloudflare:test";
+import { expect, it, vi } from "vitest";
+
+it("should be able to trigger a workflow", async () => {
+	const res = await SELF.fetch("https://mock-worker.local");
+
+	expect(res.status).toBe(200);
+});
+
+it("workflow should reach the end and be successful", async () => {
+	const res = await SELF.fetch("https://mock-worker.local");
+
+	const json = await res.json<{ id: string }>();
+
+	await vi.waitUntil(async () => {
+		const res = await SELF.fetch(`https://mock-worker.local?id=${json.id}`);
+
+		const statusJson = await res.json<{ status: string }>();
+		console.log(statusJson);
+		return statusJson.status === "complete";
+	}, 1000);
+});

fixtures/vitest-pool-workers-examples/workflows/test/tsconfig.json

@@ -0,0 +1,4 @@
+{
+	"extends": "../../tsconfig.workerd-test.json",
+	"include": ["./**/*.ts", "../src/env.d.ts"]
+}

fixtures/vitest-pool-workers-examples/workflows/tsconfig.json

@@ -0,0 +1,4 @@
+{
+	"extends": "../tsconfig.node.json",
+	"include": ["./*.ts"]
+}

fixtures/vitest-pool-workers-examples/workflows/vitest.config.ts

@@ -0,0 +1,20 @@
+import { defineWorkersProject } from "@cloudflare/vitest-pool-workers/config";
+
+export default defineWorkersProject({
+	esbuild: {
+		// Required for `using` support
+		target: "ES2022",
+	},
+	test: {
+		poolOptions: {
+			workers: {
+				singleWorker: true,
+				// FIXME(lduarte): currently for the workflow binding to work, isolateStorage must be disabled.
+				isolatedStorage: false,
+				wrangler: {
+					configPath: "./wrangler.toml",
+				},
+			},
+		},
+	},
+});